9. If 45 bushels of grain, at 75 cents per bushel, will pay a debt, how many bushels, at 1 dollar per bushel, will pay the same? cts. cts. bush. The Latin term per centum, and its abbreviation per 'cent, signify by the hundred. Thus, 1 per cent of any number is of that number; 2 per eent is 10; 3 per cent 34 per cent is 1; 5 per cent is 100; and so on. 1. What is 4 per cent of 1156 dollars? $1156 5 4 per cent is; therefore we multiply by 4 and divide by 100. To divide by 100, we need only cut off two figures from the right. Ans. 46 dollars 24 cents. $46,24 2. What is 5 per cent or T5, of $145 68 cents? 100' INTEREST. Interest is an allowance of so much per cent made by a debtor to a creditor, for the use of money. In the New England States, the rate of interest is established by law at 6 per cent per annum; that is, $6 for the use of $100, or £6 for the use of £100, for one year; and in the same proportion for a greater or less sum, or for a longer or shorter time. In New York, the lawful interest is 7 per cent, &c. 1. Principal is the sum due, for which interest is paid. 2. Rate is the sum per cent agreed on. 3. Amount is the principal and interest added together. Interest is of two kinds, Simple and Compound. SIMPLE INTEREST. Simple Interest is when interest is computed only on the original principal. 1. To find the interest of any given sum for one year. RULE. Multiply the principal by the rate per cent and divide the product by 100; the quotient will be the interest for one year. Note. By this Rule are calculated Commission, Brokerage, Insurance, buying and selling Stock, &c. EXAMPLES. 1. What is the interest of $511 for one year, at 6 per cent? Principal $511 Interest 30,66 We multiply by the rate per cent, and point off two figures for dividing by 100, and the answer is 3066 dollars, or 30 dollars 66 cents. 2. What is the interest of $1236, 38 cents for 1 year, at After multiplying by the rate per cent, we place the separatrix as in Federal money. Then to divide by 100 100 we point off two figures, and the answer is 86 dollars 5466 cents, or $86 54 cents 6m. 3. What is the interest of 341 dollars 37 cents for one year, at 5 per cent? .$341,37 5 17'06,85 After multiplying by the rate per cent and placing the separatrix as in multiplication of Federal money, we need only call the figures on the left so many cents right decimals of a cent; thus 1706,85 and those on the cents $17 6c. 85m. 3. Required the interest of $800 for one year, at 51 per cent. cent. Ans. $44. 4. Required the interest of $956,25 for one year, at 7 per cent. Ans. $66 93c. 75m. 5. Required the interest of $1356 for one year, at 6 per Ans. $81,36: 6. What is the interest of £500 for one year, at 5 per cent? Ans. £25. 7. Required the amount of $1528,25 for one year, at 4 per cent? Ans. $1589,38. 2. To calculaté interest for any number of years, months, &c. GENERAL RULE. 1. Find the interest for one year as before. 2. Multiply the interest for one year by the given number of years. 3. For the months, take even parts of a year; thus, for 1 month take of a year, and for 2 months or 1, &c. 4. For days, take even parts of a month, allowing it to contain 30 days; (or, if the sum be large and great accuracy required, work for the days by the Rule of Three Direct, by saying, as 365 days are to the interest for one year, so is the given number of days to the interest re quired.) EXAMPLES. 1. What is the interest of $84,54 for 3 years 7 months and 10 days, at 6 per cent per annum? $84,54 6 mo. of 1 year. 507,24 interest for 1 year in cts. = [mills, &c. 253,62 ditto for 6 months. of 1 mo. Answer 1831,701831cts. 7m. or $18. 2. What is the interest of 210 dollars for 5 years, at 6 per cent per annum ? Ans. $63. 3. Required the interest of $511,65 for 3 years and 4 months, at 5 per cent per annum. Ans, $85,271. 4. Of $48,25 for two and a half years, at 6 per cent Ans. $7, 23c. 71⁄2m. 5. Of 249 dollars for 3 years 9 months, at 6 per cent. Ans. $56, 2 cents. 6. Of $27,56 for 2 years, at 5 per cent. Ans. $2 75cts. 6m. 7. Of $951,17 for 4 years, at 5 per cent. Ans. $190 23cts. 4m. 8. What is the interest of $1 for 16 years 8 months, at 6 per cent per annum ? Ans. $1. 9. What is the interest of $824,41 for 3 years 5 mos. and 10da., at 6 per cent per annum? Ans. $170,35cts. 92m.+ 10. What will £1825 amount to in 5 per annum? years, at 4 per cent Ans. £2190. 11. What is the interest of $145,96 for 3 years 9 mos., at 5 per cent per annum? Ans. $28, 73c. 5m. 12. What will $15195 amount to in 5 years 4 months and 20 days, at 7 per cent? Ans. $20926, 89c. 16m.+ 13. What is the interest of $456 from April 15th, 1829, to March 5th, 1833, at 6 per cent? Ans. $106,40. 14. A note dated October 5th, 1831, for 256 dols. was paid, principal and interest, March 20th, 1834: I demand the amount paid. Interest at 6 per cent. Ans. $293,76. SHORT PRACTICAL RULES FOR CALCULATING INTEREST WHEN THE RATE IS 6 PER CENT. 1. To find the interest for any number of months at 6 per cent. In casting the interest of any sum of money for 1 year, or 12 months, at 6 per cent, it is evident that the rate per cent. is just half the number of months in a year, or onehalf per cent per month. Hence, for any term of time at 6 per cent, the rate being just per cent per month, it is evident that if we multiply the given sum by half the number of months, it will give the interest required.-Hence the following RULE. Multiply the principal by half the number of months, and divide the product by 100; the quotient will be the interest for the given time. EXAMPLES. 1. What is the interest of $148,21 for 1 year 4 months, or 16 months, at 6 per cent per annum? Principal $148,21 Half the months 8 11/85,68 After placing the separatrix in the product, we point off the 2 right hand 'figures (for dividing by 100.) $11 85c. 68m. 2. What is the interest of $225 for 3 years and 4 mos. at 6 per cent per annum ? Ans. $45,00. 3. What is the interest of $95 34 for 9 months, at 6 per cent? Ans. $4, 29+. 4. Required the interest of $211,25 for 7 months, at 6 per cent. Ans. $7, 39c. 37m.+ 5. Required the interest of $137 for 2 months, at 6 per cent? Ans. $1, 37c. 6. What is the interest of £125 for 8 months, at 6 per Ans. £5. cent ? |