The legal rate of interest varies in the different States as shown by the following table: INTEREST LAWS IN THE UNITED STATES. Laws of each State and Territory regarding Rates of Interest and Penalties for Usury, with the Law or Custom as to Days of Grace on Notes and Drafts. By an amendment of the law New York has legalized any rate of interest upon call loans of $5,000 or upward, on coilateral security. For convenience in computing interest, 30 days are generally considered a month, and 360 days a year. ART. 318.-To find the interest or amount when the principal, time and rate are given. ORAL EXERCISES. 1. What is the interest on $50 for 1 year 4 months 10 days at 6% ? Solution. The interest for 1 year at 6% is .06 of the principal, or $3, and for 1 month it is of that sum, or 25 cents, and for 16 months it is 163 times 25 cents, or $4.083. What is the interest on : 2. $80 for 2 years at 6% ? 3. $40 for 3 years at 5% ? 4. $100 for 1 year 6 months at 7% ? 5. $200 for 2 years 8 months at 8% ? 6. $300 for 3 years 6 months 24 days at 6% ? 8. $200 for 3 years 7 months at 6% ? 9. $400 for 2 years 5 months at 6% ? 10. $200 for 1 year 9 months 18 days at 6% ? WRITTEN EXERCISES. 1. What is the interest on $360 for 3 yr. 8 mo. and 15 days at 8% ? ART. 319.-Rule for computing interest.-Muitiply the principal by the rate per cent., divide the product by 12, and multiply the quotient by the total number of months and tenths of a month for which interest is required. NOTE. Since 30 days make an interest month, the given number of days divided by 3 gives tenths of a month. Thus, 9 days = .3; 12 days.4; 13 days.4; 26 days.83, and so on. 9. $516.60 for 3 yr. 7 mo. 15 da. at 61%? 10. $628.45 for 2 yr. 9 mo. 10 da. at 81% ? 11. What is the amount of $317.15 for 3 yr. 1 mo. 9 da. at 4% ? 12. What is the amount of $384.23 for 2 yr. 24 da. at 5% ? 13. What is the amount of $392.38 for 3 mo. 10 da. at 6% ? 14. What is the amount of $421.31 for 1 mo. 20 da. at 7% ? 15. What is the amount of $521.37 for 16 at 6% ? yr. 8 mo. 16. What is the amount of $492.33 for 24 da. at 8%? 17. A loaned $475, June 30, 1885: how much was due him March 17, 1886, interest at 5%? 18. If you loan $324.75, January 4, 1885, how much will be due you October 1, 1886, interest at 7% ? 19. On the 23d of February, 1884, Mr. Brown borrowed $758.84: how much did he owe April 1, 1886, interest at 6% ? ART. 320.-Six Per Cent. Method. 1. What is the interest on $360 for 3 yr. 8 mo. 15 da. at 8% ? Analysis. The interest on $1 for 1 yr. at 6% is $.06; the interest for 1 mo. is of $.06 $.005, and the interest for 1 da. is 3% of $.005 $.000. Hence, the interest for 3 yr. is $.18; for 8 mo., $.04, and for 15 da., $.0025, the sum of which is $.2225. But 8% is of 6%, and & of $.2225 is $.293; and since the interest on $1 for the given time at 8% is $.293, the interest on $360 is 360 times $.293 = $106.80. Rule for finding interest on any principal for any time at any rate per cent.-Multiply $.06 by the number of years; $.005, by the number of months, and $.000 by the number of days; add the partial products, take the fractional part of it that the given rate is of 6%, and multiply this by the principal expressed decimally. What is the interest on— 2. $75.50 for 1 year 6 months 18 days at 6% ? 5. $749.48 for 6 years 5 months 5 days at 6% P 6. $1,800.18 for 1 year 7 months 7 days at 5% ? 7. What is the amount of $500 for 2 years 3 months 2 days at 7% ? 8. What is the amount of $480.99 for 11 years 11 months 11 days at 8% ? 9. What is the amount of $75 for 16 years 8 months at 6% ? 10. Illustrate by an original problem the method of calculating interest by the six per cent. method. ART. 321.-Exact Interest. The usual way of computing interest is based on 360 days to the year. By the exact method the actual number of days is found and is regarded as so many 365ths of a year. This rule is the one adopted by banks and the United States Government, and it is growing in favor among business men. When the time in days is less than 1 year, the exact interest is found by first calculating the interest according to the methods already given, and deducting from the result for the common years and for the leap years. 11. What is the exact interest on $234 from July 1, to October 31, at 6% ? 12. What is the exact interest on $563.54 from January 16, 1884, to March 10, of the same year, the rate being 7% ? 13. What is the exact interest on $907.95 from January 1, 1886, to December 1, 1886, the rate being 10%? 14. What is the difference between common and exact interest on $784.96 at 6% from Christmas, 1886, to July 4, 1887 ? 15. Illustrate by an original problem the method of computing exact interest. |