Engineering Economics | 暗記メーカー

1

An employee is earning P18,000 a month and he can only afford to purchase a car, which will require a down payment of P85,000 and a monthly amortization of 30% of his monthly salary. What would be the maximum cash value of a car he can purchase if the seller will agree to a down payment of P85,000 and the balance payable in four years at 18% per year payable on monthly basis. The first payment will be due at the end of the first month.

268,830

2

Peter borrows P10,000 from a bank on the first days of the month. The interest is computed at the end of every month on the amount he still owed at the rate of 1.5% per month. Peter pays “x” pesos at the end of the first month, another “x” at the end of the second month and another “x” at the end of the 3rd month. Peter has completely paid off the debt completely at the end of the 3rd month, find the value of “x”.

3434

3

A man bought a government bond which cost P1000 and will pay P50 interest each year for 20 yrs. The bond will mature at the end of 20 years and he will receive the original P1000. If there is 2% annual inflation during this period, what rate of return will the investor receive after considering the effect of inflation?

2.94%

4

The first cost of a machine is P1,800,000 with a salvage value of P300,000 at the end of its life of 5 yrs. Determine the total depreciation after 3 yrs. using Sum of Years Digit Method.

P1,200,000

5

The first cost of a machine is P1,800,000 with a salvage value of P300,000 at the end of its life of 5 yrs. Determine the total depreciation after 3 yrs. using Constant Percentage Method.

P1,185,770

6

A machine costs P900,000 and will have a salvage value of P450,000 when retired at the end of 5 yrs. Using the sum of years digit method, what is the sum of the depreciation cost in the first two years.

P270,000

7

A man wished to have P40,000 in a certain fund at the end of 8 years that will pay a nominal rate of 6% compounded continuously. What is the value of the compound amount factor for this rate?

1.616

8

An equipment installation job of Diego Construction in the completion stage can be completed in 40 days of 8 hrs. per day of work with 40 men working. With the contract expiring in 30 days, the contractor decided to add 10 men on the job, overtime not being permitted. If the liquidated damages P20,000 per day of delay, and the men are paid P580 per day, compute the total cost if he will add 10 more men to finish the job.

P968,000

9

In 1940, the average value of a house is P290,000. In 1990, the average value of a house of the same model is P7,910,000. What was the rate of inflation for the house?

6.8%

10

A broadcasting corporation was formed duly approved by the Securities and Exchange office has a working capital of P20 M and a fixed capital of P80 M. Annual depreciation amounts to P5 M and expected annual profit is P16 M. Determine the recovery period in years.

6.25

11

A businessman wishes to earn 7% on his capital after payment of taxes. If the income from an available investment will be taxed at an average rate of 42% what minimum rate of return before payment of taxes must the investment offer to be justified?

12.1%

12

If money is inverted at a nominal rate of interest of 8% for a period of 4 yrs., what is the value of the compound amount factor if it is compounded continuously?

1.377

13

The cost of equipment is P500,000 and the cost of installation, labor, taxes and miscellaneous expenses is P30000. If the salvage value is 10% of the cost of equipment at the end of its life of 5 years, compute the book value at the end of the 3rd year using MARCS Method.

152,640

14

A telephone company purchased a microwave radio equipment for P6M. If the equipment shall be depreciated over a period of 8 yrs. with a salvage value of 5% of the cost of the equipment, determine the worth of the equipment on the 4th year after deducting depreciation charges using MARCS Method.

2.215M

15

A telephone company purchased a microwave equipment for P6 million with a salvage value of P600,000 over a period of 5 years and pay a lump sump of P400,000 for the maintenance cost. Minimum attractive rate of return is 16% annually. Compute the annual cost of investment of purchasing the microwave equipment.

1,867,374.41

16

A machine costs P100,000 with a salvage value of P20,000 at the end of its life of 8 years. Which of the following gives the depreciation at the 6th year using sinking fund method if money is worth 6% annually.

8082.88

17

A machine was purchased at an original cost of P400,000.00 with a salvage value of P20,000.00. Life of this machine is expected to last for 6 years. It was used for 4000 hrs. in the first year, 6000 hrs. in the second year and 8000 hrs. on the third year. The machine is expected to last for 3800 hours in the period of 6 years. Which of the following gives the depreciation at the end of the second year.

60,000

18

A fixed capital investment of P10,000,000 is required for a proposed manufacturing plant and an estimated working capital of P2,000,000. Annual depreciation is estimated to be 10% of the fixed capital investment. If the annual profit is P2500000. what is the rate of return?

20.83%

19

A contractor has 50 men of the same capacity at work on a job. They can complete the job in 30 days, the working day being 8 hours, but the contract expire in 20 days. He decides to put 20 additional men. If all the men get P3.00 per day for a full or part day and if the liquidated damages are P100 for every full or part day he requires over his contract. How many days could he finish the job.

22

20

A construction equipment is badly needed for a certain project so as to shorten the time of completion of the project. The equipment cost P1.2 million and has a life of 5 yrs. with a salvage value of P200,000 at the end of its life. This machine can be bought with money borrowed at an interest rate of 20% per annum. Annual operating cost is P10,000. Find the annual investment cost of using the equipment.

384,380

21

Suppose a company wants to have $450,000 after 2 1/2 years to modernize its production equipment. How much of each previous quarter’s profits should be deposited at the beginning of the current quarter to reach this goal, if the company’s investment earns 6.8%, compounded quarterly?

$40,967.39

22

What is the present value of an annuity of $1500 payable at the end of each 6-month period for 2 years if money is worth 8%, compounded semiannually?

$5444.84

23

Find the lump sum that one must invest in an annuity in order to receive $1000 at the end of each month for the next 16 years, if the annuity pays 9%, compounded monthly.

$101,572.77

24

Suppose that a couple plans to set up an ordinary annuity with a $100,000 inheritance they received. What is the size of the quarterly payments they will receive for the next 6 years (while their children are in college) if the account pays 7%, compounded quarterly?

$5138.57

25

An inheritance of $250,000 is invested at 9%, compounded monthly. If $2500 is withdrawn at the end of each month, how long will it be until the account balance is $0?

186 months

26

Suppose a 15-year corporate bond has a maturity value of $10,000 and coupons at 5% paid semiannually. If an investor wants to earn a yield of 7.2% compounded semiannually, what should he or she pay for this bond?

$8001.99

27

A lottery prize worth $1,200,000 is awarded in payments of $10,000 at the beginning of each month for 10 years. Suppose money is worth 7.8%, compounded monthly. What is the real value of the prize?

$836,843.55

28

Suppose that a court settlement results in a $750,000 award. If this is invested at 9%, compounded semiannually, how much will it provide at the beginning of each half-year for a period of 7 years?

$70,205.97

29

A deferred annuity is purchased that will pay $10,000 per quarter for 15 years after being deferred for 5 years. If money is worth 6% compounded quarterly, what is the present value of this annuity?

$292,386.85

30

Suppose a lottery prize of $50,000 is invested by a couple for future use as their child’s college fund. The family plans to use the money as 8 semiannual payments at the end of each 6-month period after payments are deferred for 10 years. How much would each payment be if the money can be invested at 8.6% compounded semiannually?

$17,451.26

31

The communications system for Conglomerate Engineering cost $50,000 four years ago. Its current salvage value is $26,000, which will decline as follows over the next 4 years: $20,000, $16,250, $14,000, and $12,500. The O&M costs will be $6000 this year, and these costs will increase by $2000 per year. At Conglomerate’s interest rate of 10%, the best challenger has an EAC of $14,200. When should the communications system be replaced?

the communications system should not be replaced yet

32

The roof and ceiling of a commercial building will be insulated by blown-in insulation, which can be specified in 1-inch-depth increments. The minimum amount of insulation that will meet code is 6 inches, and the maximum amount that will fit is 12 inches. What is the optimal depth of this insulation? The firm uses an interest rate of 8% and a 30-year building life. The installed cost of the insulation for the 10,000-square-foot ceiling is $1.75 per cubic foot. Thicker insulation will reduce the capacity of the HVAC equipment and the annual heating and cooling costs. With 6 inches of insulation, the annual bill for heat gains and losses through the roof will be $1200. Insulation thickness 6" 7" 8" 9" 10" 11" 12" HVAC first cost $10,000 9643 9375 9167 9000 8864 8750

best insulation thickness is 8 inches

33

Assume that a light bulb has an average life of 22,000 hours; one-fifth of the bulbs fail at 20,000, 21,000, 22,000, 23,000, and 24,000 hours. The facility operates every hour of the year, and the bulbs are always on. Each bulb costs $3.50 to buy, $1.50 to install individually, and $.25 to install in block replacement. At least 60% of the bulbs must be operating for adequate light. The firm’s interest rate is 10%. Compare block replacement at 21,000 hours with individual replacement.

EAC(individual) = $2.44 and EAC(block) - $1.90 per bulb

34

North Central Power & Light has just purchased a generating unit that comes with a 2-year warranty. Once the warranty expires, repair costs are expected to average $3500 per year. Find the EAC for the repair costs over the 15-year life of the generating unit. The interest rate is 7%.

$2805

35

For 40 years, Wishbone Hill has been notorious for the accidents that have occurred there. Railings, signs, wider shoulders, etc. have only managed to keep the increasing level of traffic from increasing the rate of accidents. The highway department uses an interest rate of 6% and a study period of 40 years. What is the EAC for building another two-lane road to separate the traffic by direction? Purchasing the right-of-way is expected to cost $15M, and construction is expected to cost $60M. Snowplowing, painting, repair of guardrails, and periodic pavement work is expected to cost $3M per year.

$7.99M

36

The National Monuments Commission is considering the imposition of viewing fees for several monuments. At one monument, these fees would bring in $800K for the first year, and this should increase by $50K per year as the number of tourists increases. If the government uses an interest rate of 10% and perpetual life is assumed, what is the EAW for the income stream?

$1.3M

37

Crystal Lake Village is building a sewage treatment facility that has a 35-year design life. This facility includes a pump that costs $13,000 and that will last 7 years. The pump has no salvage value, and its energy costs are included with other energy costs. If i = 8%, find the EAC for the series of five pumps.

$2497

38

George graduated in civil engineering 10 years ago, and his mother and her two sisters are ready to let him open a branch office of their firm in another state. Their pattern is to own only one grader, one Caterpillar tractor (cat), one loader, and two tractor trailers for hauling at any time. If more machinery is needed, they hire it, just as they hire all dump trucks or belly dumps. Use an interest rate of 10% and a study period of 30 years to find the EAC of the owned equipment.

$352K

39

Golden Valley Manufacturing sponsors a student loan program for the children of employees. No interest is charged until graduation, and then the interest rate is 5%. Assume that George borrows $8000 per year at the beginnings of years 1 through 4 and that he graduates at the end of year 4. If equal annual payments are made at the ends of years 5 through 9, what is the internal rate of return for George’s loan? Is this attractive to George?

2.66%, yes

40

A new landfill site is being considered. It would save the citizens of Shady Acres $250,000 per year in the fees they pay a private firm for garbage pickup. The citizens who live near the road to the landfill site, and especially those who live closest to the site, are not supportive. A local university economist has estimated the disbenefits of truck traffic, noise, and odor to be $120,000 per year. The new landfill will cost $2.4 million, and it will last 40 years. Shady Acres uses an interest rate of 6%. Calculate the benefit/cost ratio using equivalent annual measures.

0.815

41

A deferred annuity is purchased that will pay $10,000 per quarter for 15 years after being deferred for 5 years. If money is worth 6% compounded quarterly, what is the present value of this annuity?

$292,386.85

42

A broadcasting corporation was formed duly approved by the Securities and Exchange office has a working capital of P20 M and a fixed capital of P80 M. Annual depreciation amounts to P5 M and expected annual profit is P16 M. Determine the recovery period in years.

6.52

43

How much more will you earn if you invest $1000 for 5 years at 8% compounded continuously instead of at 8% compounded quarterly?

$5.87

44

Suppose a lottery prize of $50,000 is invested by a couple for future use as their child’s college fund. The family plans to use the money as 8 semiannual payments at the end of each 6-month period after payments are deferred for 10 years. How much would each payment be if the money can be invested at 8.6% compounded semiannually?

$17,451.26

45

The cost of equipment is P500,000 and the cost of installation, labor, taxes and miscellaneous expenses is P30000. If the salvage value is 10% of the cost of equipment at the end of its life of 5 years, compute the book value at the end of the 3rd year using MARCS Method.

152,640

46

Twin 1 invests $2000 at the end of each of 8 years in an account that earns 10%, compounded annually. After the initial 8 years, no additional contributions are made, but the investment continues to earn 10%, compounded annually, for 36 more years (until twin 1 is age 65). How much does twin 1 have at age 65?

$707,028

47

Assume that a light bulb has an average life of 22,000 hours; one-fifth of the bulbs fail at 20,000, 21,000, 22,000, 23,000, and 24,000 hours. The facility operates every hour of the year, and the bulbs are always on. Each bulb costs $3.50 to buy, $1.50 to install individually, and $.25 to install in block replacement. At least 60% of the bulbs must be operating for adequate light. The firm’s interest rate is 10%. Compare block replacement at 21,000 hours with individual replacement

EAC(individual) = $2.44 and EAC(block) - $1.90 per bulb

48

A machine costs P100,000 with a salvage value of P20,000 at the end of its life of 8 years. Which of the following gives the depreciation at the 6th year using sinking fund method if money is worth 6% annually.

8082.88

49

A company establishes a sinking fund to discharge a debt of $300,000 due in 5 years by making equal semiannual deposits, the first due in 6 months. If the deposits are placed in an account that pays 6%, compounded semiannually, what is the size of the deposits?

$26,169.15

50

The National Monuments Commission is considering the imposition of viewing fees for several monuments. At one monument, these fees would bring in $800K for the first year, and this should increase by $50K per year as the number of tourists increases. If the government uses an interest rate of 10% and perpetual life is assumed, what is the EAW for the income stream?

$1.3M

51

A contractor has 50 men of the same capacity at work on a job. They can complete the job in 30 days, the working day being 8 hours, but the contract expire in 20 days. He decides to put 20 additional men. If all the men get P3.00 per day for a full or part day and if the liquidated damages are P100 for every full or part day he requires over his contract. How many days could he finish the job.

22

52

Peter borrows P10,000 from a bank on the first days of the month. The interest is computed at the end of every month on the amount he still owed at the rate of 1.5% per month. Peter pays “x” pesos at the end of the first month, another “x” at the end of the second month and another “x” at the end of the 3rd month. Peter has completely paid off the debt completely at the end of the 3rd month, find the value of “x”.

3434

53

Golden Valley Manufacturing sponsors a student loan program for the children of employees. No interest is charged until graduation, and then the interest rate is 5%. Assume that George borrows $8000 per year at the beginnings of years 1 through 4 and that he graduates at the end of year 4. If equal annual payments are made at the ends of years 5 through 9, what is the internal rate of return for George’s loan? Is this attractive to George?

2.66%, yes

54

What is the present value of an annuity of $1500 payable at the end of each 6-month period for 2 years if money is worth 8%, compounded semiannually?

$5444.84

55

The first cost of a machine is P1,800,000 with a salvage value of P300,000 at the end of its life of 5 yrs. Determine the total depreciation after 3 yrs. using Constant Percentage Method.

P1,185,770

56

An inheritance of $250,000 is invested at 9%, compounded monthly. If $2500 is withdrawn at the end of each month, how long will it be until the account balance is $0?

186 months

57

An equipment installation job of Diego Construction in the completion stage can be completed in 40 days of 8 hrs. per day of work with 40 men working. With the contract expiring in 30 days, the contractor decided to add 10 men on the job, overtime not being permitted. If the liquidated damages P20,000 per day of delay, and the men are paid P580 per day, compute the total cost if he will add 10 more men to finish the job

P968,000

58

Mary Spaulding bought Wind-Gen Electric stock for $6125.00. After 6 months, the value of her shares had risen by $138.00 and dividends totaling $144.14 had been paid. Find the simple interest rate she earned on this investment if she sold the stock at the end of the 6 months

9.2%

59

Suppose that a court settlement results in a $750,000 award. If this is invested at 9%, compounded semiannually, how much will it provide at the beginning of each half-year for a period of 7 years?

$70,205.97

60

A businessman wishes to earn 7% on his capital after payment of taxes. If the income from an available investment will be taxed at an average rate of 42% what minimum rate of return before payment of taxes must the investment offer to be justified?

12.1%

61

Suppose a young couple such as Jim and Eden from our Application Preview found three different investment companies that offered college savings plans: (a) one at 10% compounded annually, (b) another at 9.8% compounded quarterly, and (c) a third at 9.65% compounded continuously. Find the annual percentage yield (APY) for each of these three plans to discover which plan is best.

9.8% compounded quarterly is best

62

The communications system for Conglomerate Engineering cost $50,000 four years ago. Its current salvage value is $26,000, which will decline as follows over the next 4 years: $20,000, $16,250, $14,000, and $12,500. The O&M costs will be $6000 this year, and these costs will increase by $2000 per year. At Conglomerate’s interest rate of 10%, the best challenger has an EAC of $14,200. When should the communications system be replaced?

the communications system should not be replaced yet

63

A telephone company purchased a microwave radio equipment for P6M. If the equipment shall be depreciated over a period of 8 yrs. with a salvage value of 5% of the cost of the equipment, determine the worth of the equipment on the 4th year after deducting depreciation charges using MARCS Method.

2.215 M

64

A small business invests $1000 at the end of each month in an account that earns 6% compounded monthly. How long will it take until the business has $100,000 toward the purchase of its own office building?

82 months

65

North Central Power & Light has just purchased a generating unit that comes with a 2-year warranty. Once the warranty expires, repair costs are expected to average $3500 per year. Find the EAC for the repair costs over the 15-year life of the generating unit. The interest rate is 7%.

$2805

66

A machine was purchased at an original cost of P400,000.00 with a salvage value of P20,000.00. Life of this machine is expected to last for 6 years. It was used for 4000 hrs. in the first year, 6000 hrs. in the second year and 8000 hrs. on the third year. The machine is expected to last for 3800 hours in the period of 6 years. Which of the following gives the depreciation at the end of the second year.

60,000

67

Find the future value of an investment if $150 is deposited at the beginning of each month for 9 years and the interest rate is 7.2%, compounded monthly.

$22,836.59

68

Crystal Lake Village is building a sewage treatment facility that has a 35-year design life. This facility includes a pump that costs $13,000 and that will last 7 years. The pump has no salvage value, and its energy costs are included with other energy costs. If i = 8%, find the EAC for the series of five pumps

$2497

69

A construction equipment is badly needed for a certain project so as to shorten the time of completion of the project. The equipment cost P1.2 million and has a life of 5 yrs. with a salvage value of P200,000 at the end of its life. This machine can be bought with money borrowed at an interest rate of 20% per annum. Annual operating cost is P10,000. Find the annual investment cost of using the equipment.

384,380

70

A man bought a government bond which cost P1000 and will pay P50 interest each year for 20 yrs. The bond will mature at the end of 20 years and he will receive the original P1000. If there is 2% annual inflation during this period, what rate of return will the investor receive after considering the effect of inflation?

2.94%

71

A new landfill site is being considered. It would save the citizens of Shady Acres $250,000 per year in the fees they pay a private firm for garbage pickup. The citizens who live near the road to the landfill site, and especially those who live closest to the site, are not supportive. A local university economist has estimated the disbenefits of truck traffic, noise, and odor to be $120,000 per year. The new landfill will cost $2.4 million, and it will last 40 years. Shady Acres uses an interest rate of 6%. Calculate the benefit/cost ratio using equivalent annual measures

0.815

72

Find the lump sum that one must invest in an annuity in order to receive $1000 at the end of each month for the next 16 years, if the annuity pays 9%, compounded monthly

$101,572.77

73

A machine costs P900,000 and will have a salvage value of P450,000 when retired at the end of 5 yrs. Using the sum of years digit method, what is the sum of the depreciation cost in the first two years.

P270,000

74

Suppose a 15-year corporate bond has a maturity value of $10,000 and coupons at 5% paid semiannually. If an investor wants to earn a yield of 7.2% compounded semiannually, what should he or she pay for this bond?

$8001.99

75

In 1940, the average value of a house is P290,000. In 1990, the average value of a house of the same model is P7,910,000. What was the rate of inflation for the house?

6.8%

76

If $1000 is invested at 5.8% simple interest, how long will it take to grow to $1100?

1.72 years

77

A deferred annuity is purchased that will pay $10,000 per quarter for 15 years after being deferred for 5 years. If money is worth 6% compounded quarterly, what is the present value of this annuity?

$292,386.85

78

If money is inverted at a nominal rate of interest of 8% for a period of 4 yrs., what is the value of the compound amount factor if it is compounded continuously?

1.377

79

Richard Lloyd deposits $200 at the end of each quarter in an account that pays 4%, compounded quarterly. How much money will he have in his account in 2 ¼ years?

$1873.71

80

The roof and ceiling of a commercial building will be insulated by blown-in insulation, which can be specified in 1-inch-depth increments. The minimum amount of insulation that will meet code is 6 inches, and the maximum amount that will fit is 12 inches. What is the optimal depth of this insulation? The firm uses an interest rate of 8% and a 30-year building life. The installed cost of the insulation for the 10,000-square-foot ceiling is $1.75 per cubic foot. Thicker insulation will reduce the capacity of the HVAC equipment and the annual heating and cooling costs. With 6 inches of insulation, the annual bill for heat gains and losses through the roof will be $1200. Insulation thickness 6" 7" 8" 9" 10" 11" 12" HVAC first cost $10,000 9643 9375 9167 9000 8864 8750 A. best insulation thickness is 10 inches

best insulation thickness is 8 inches

81

A telephone company purchased a microwave equipment for P6 million with a salvage value of P600,000 over a period of 5 years and pay a lump sump of P400,000 for the maintenance cost. Minimum attractive rate of return is 16% annually. Compute the annual cost of investment of purchasing the microwave equipment

1,867,374.41

82

A young couple wants to save $50,000 over the next 5 years and then to use this amount as a down payment on a home. To reach this goal, how much money must they deposit at the end of each quarter in an account that earns interest at a rate of 5%, compounded quarterly?

$2216.02

83

For 40 years, Wishbone Hill has been notorious for the accidents that have occurred there. Railings, signs, wider shoulders, etc. have only managed to keep the increasing level of traffic from increasing the rate of accidents. The highway department uses an interest rate of 6% and a study period of 40 years. What is the EAC for building another two-lane road to separate the traffic by direction? Purchasing the right-of-way is expected to cost $15M, and construction is expected to cost $60M. Snowplowing, painting, repair of guardrails, and periodic pavement work is expected to cost $3M per year.

$7.99M

84

A fixed capital investment of P10,000,000 is required for a proposed manufacturing plant and an estimated working capital of P2,000,000. Annual depreciation is estimated to be 10% of the fixed capital investment. If the annual profit is P2500000. what is the rate of return?

20.83%

85

An employee is earning P18,000 a month and he can only afford to purchase a car, which will require a down payment of P85,000 and a monthly amortization of 30% of his monthly salary. What would be the maximum cash value of a car he can purchase if the seller will agree to a down payment of P85,000 and the balance payable in four years at 18% per year payable on monthly basis. The first payment will be due at the end of the first month.

268,830

86

George graduated in civil engineering 10 years ago, and his mother and her two sisters are ready to let him open a branch office of their firm in another state. Their pattern is to own only one grader, one Caterpillar tractor (cat), one loader, and two tractor trailers for hauling at any time. If more machinery is needed, they hire it, just as they hire all dump trucks or belly dumps. Use an interest rate of 10% and a study period of 30 years to find the EAC of the owned equipment.

$352K

87

Suppose a company wants to have $450,000 after 2 1/2 years to modernize its production equipment. How much of each previous quarter’s profits should be deposited at the beginning of the current quarter to reach this goal, if the company’s investment earns 6.8%, compounded quarterly?

$40,967.39

88

The first cost of a machine is P1,800,000 with a salvage value of P300,000 at the end of its life of 5 yrs. Determine the total depreciation after 3 yrs. using Sum of Years Digit Method.

P2,000,000

89

Suppose that a couple plans to set up an ordinary annuity with a $100,000 inheritance they received. What is the size of the quarterly payments they will receive for the next 6 years (while their children are in college) if the account pays 7%, compounded quarterly?

$5138.57

90

A man wished to have P40,000 in a certain fund at the end of 8 years that will pay a nominal rate of 6% compounded continuously. What is the value of the compound amount factor for this rate?

1616

91

A lottery prize worth $1,200,000 is awarded in payments of $10,000 at the beginning of each month for 10 years. Suppose money is worth 7.8%, compounded monthly. What is the real value of the prize?

$836,843.55

92

Find the EAC for a building that has life of 90years, a first cost of $1.2M, and no salvage value. The building will be repainted every 5years for $80K, reshingled every 15years for $225K, and repumbled and rewired every 30years for $750K. Find the EAC if i=10%

$144.8K

93

Ilene has decided to celebrate earning here P.E. license by buying a condo. Her bank has told her that she can qualify for a $100,000, 30year mortgage at the current nominal interest rate of 9 1/4%. The monthly payment at the rate is $822.68. She believes she can afford to pay 10% more than that. If she makes the extra payment each month, how soon will her mortgage be paid off?

20.7 years

94

A producer can sell x items per week at a price P=200-0.01x cents, and it costs 50x+20,000 cents to make x items. What is the most profitable number to make?

7500