CHAPTER XII.

SIMPLE AND COMPOUND INTEREST.- DISCOUNT. — CAUSE AND EFFECT. - PARTNERSHIP. - BONDS AND STOCKS.

EXCHANGE. LONGITUDE AND TIME. SURFACES AND VOLUMES.

TO FIND PRINCIPAL, RATE, OR TIME.

931. At what rate per cent will $723.60 amount to $759.78 in 1 yr. 1 mo. 10 da. ?

932. In what time will $85.50 produce $8.17 interest, at 4 per cent?

804

3618 :4층

Ans. 4 per cent.

933. Slate Exercises.

Find rate, time, etc.

1. Principal, $2,000; time, 3 yr.; interest, $300. Rate? 2. Principal, $1,800; rate, 4%; interest, $144. Time? 3. Time, 8 mo.; rate, 41%; interest, $2.88. Principal? 4. Principal, $38; time, 2 yr.; amount, $40.28. Rate? 5. Principal, $140; rate, 31%; time, 3 mo. 15 da. Interest? 6. Amount, $39.60; rate, 4%; time, 2 yr. 6 mo. Principal? 7. Amount, $484.15; rate, 31%; principal, $460. Time? 8. Principal, $39.60; rate, 4%; time, 1 yr. 7 mo. 15 da. Amount?

9. Time, 8 yr.; rate, 3%; amount, $6,200. Principal? 10. Principal, $7,548; time, 3 mo. 5 da.; interest, $119.51. Rate?

11. Principal, $9,000; rate, 4%; interest, $632. Time?

12. Time, 2 yr. 3 mo. 20 da.; rate, 5%; amount, $160.60. Principal?

13. Principal, $756; rate, 31%; time, 3 yr. 4 mo. 20 da. Interest?

14. Principal, $120; time, 1 yr. 2 mo. 15 da.; interest, $4.35. Rate?

15. Amount, $97.57; rate, 4%; interest, $7.57. Time?

16. Time, 3 yr. 8 mo. 19 da; rate, 41%; amount, $93.39. Principal?

17. Principal, $1,848; rate, 33%; time, 4 yr. 9 mo. 25 da. Amount?

18. Rate, 5%; time, 4 yr. 6 mo. 23 da.; interest, $16.43. Principal?

19. Rate, 3%; amount, $3,651.90; interest, $51.90. Time? 20. Principal, $60; amount, $73.91; time, 3 yr. 10 mo. 11 da. Rate?

21. Amount, $196.92; rate, 4%; time, 2 yr. 4 mo. 6 da. Interest?

22. Interest, $27.82; rate, 5%; time, 1 yr. 5 mo. 25 da. Amount?

23. Principal, $9,000; rate, 4%; interest, $37. Time?

24. Principal, $14.40; time, 3 yr. 9 mo. 20 da. ; interest, $2.74. Rate?

25. Amount, $147.59; rate, 21%; interest, $3.59. Time?

934. Oral Exercises.

1. In what time will $100 amount to $109, at 6% interest? 2. At what rate will $200 produce $16 interest in 2 years? 3. What principal will produce $ 12 interest in 3 years, at 4%? 4. In what time will $300, at 4%, produce $29 interest? 5. In what time will $170 produce $1.70 interest, at 5%? 6. In what time will $360 produce $3.60 interest, at 4%? 7. In what time will $725 produce $7.25 interest, at 6%? 8. In what time will $45 produce 45¢ interest, at 41%? 9. In what time will $72 produce $1.44 interest, at 6%? 10. Find the interest on $84 for 144 days, at 5%. 11. Find the interest on $125, at 5%, for 2 months 12 days. 12. At what rate will $64 produce 64 interest in 80 days? 13. At what rate will $40 produce $1.20 interest in 6 months? 14. A certain principal produces $120 interest, at 6%. What would be the interest if the rate were 4%?

15. A man borrows $1,000, at 4%, and loans it at 6%. What is his profit in 21 years?

16. What is the interest on $240, for 3 years, at 5% ?

17. Find the interest on $1,420, at 4%, for 6 months?

18. What is the interest on $60, at 6%, for 11 months 29 days?

19. Find the amount of $250, at 5%, for 2 years.

20. What is the interest on $90, at 4%, for 99 days?

935. U. S. Civil Service. Copyist Examination.

1. Add the following, placing the sum at the bottom:

79,654,321,908.25

47,776,013,705.30

92,773,331,693.25

7,774,910,236.15

44,297,793,329.37

6,105,723,266.57

132,173.63

8,857,367,397.45

42,233,001,764.86

63,437,476,074.03

3,335,602,047.90

173,827,764,501.77

2. Express the following in figures: One billion ten million eleven thousand twenty, and (decimal) one thousand twentyfive ten-millionths.

3. Express the following in sign and figures: Ten billion one hundred ten million one hundred thousand five dollars six cents and three and three-tenths mills.

4. Express in words the following figures, signs, and abbreviations: 1⁄2 of (6 hhd. 1 bbl. 16 gal. 2 qt. — 1 bbl. 2 qt.) = 6 hhd.

6. Add .5, .05, .125, .0625, and divide the sum by 2. (Express answer in decimal fraction.)

7. A merchant purchased 540 bushels of potatoes at 90 per bushel, lost 30% of them by fire, and sold the remainder at $1.10 per bushel. Did he gain or lose, and how much?

8. A miller grinds for customers 3,600 bushels of wheat, taking from each bushel 4 quarts as toll. How much does he receive for the work, wheat being worth 621 per bushel?

9. A man purchased a house, paying for it in four payments as follows: On the first payment of the purchase price; on the second payment of the remainder; on the third payment of what then remained due; and on the last payment $2,000. What was the full amount paid for the house?

10. A field 250 feet long and 125 feet wide is enclosed by a tight board fence 6 feet high. What will it cost to paint the outside of the fence at 121 per square yard?

INTEREST BY ALIQUOT PARTS.

936. Slate Exercises.

1. Find the interest on $387.45, for 2 yr. 8 mo. 18 da., at 7%.

$387.45 x .07.

$27.1215 interest for 1 year.
27.1215 interest for 1 year.

13.5607 interest for 6 months.

4.5202 interest for 2 months.
1.1301 interest for 15 days.

.2260 interest for 3 days.