PERCENTAGE. SECTION XI. 160. PERCENTAGE, or PER CENT., denotes any number of hundredths of a given sum. OBS. These terms are from two Latin words, per and centum, which signify by the hundred. 161. The per cent. is sometimes called the rate and is expressed in decimals, thus : — OBS. When the parts of 1 per cent. cannot be expressed exactly in decimals, they should be written in the form of a common fraction, thus: 4 per cent. = =.04. 162. To find the per cent. of any number, RULE. Multiply the given number by the per cent. and point off the product, as in multiplication of decimals. The principle of this rule is the same as that in the multiplication of decimals. What does percentage, or per cent., denote? What are the terms derived from? What is the per cent. sometimes called, and how is it expressed? How are the parts of 1 per cent. written? 1. What is 4 per cent. of 144? 144 .044 576 48 6.24 Multiplying 144 by 43, and pointing off according to the rule in the multiplication of decimals, gives 6.24. EXAMPLES. 2. What is 6 per cent. of $34.556 ? 3. What is 5 per cent. of $90.755? 4. What is 4 per cent. of $875.25? 5. What is 3 per cent. of $456.675 ? 6. What is 2 per cent. of $640.205 ? 7. What is 1 per cent. of $735.75 ? 8. What is 10 per cent. of $905.60 ? 9. What is 6 per cent. of $45.305? 10. What is 4 per cent. of $734.02 ? 11 What is 1 per cent. of $560.24? per cent. of $84.50 ? per cent. of $93.60 ? 12. What is 13. What is 14. What is 15. What is per cent. of $56.49 ? per cent. of $81.90 ? 16. A man paid 6 per cent. for the use of $175.50 for 1 year. How much did he pay? 17. A man bought 15 shares of railroad stock, at $100 a share, and sold them at 9 per cent. advance? What did he gain? 18. A merchant bought 450 barrels of flour, at $4.37 per barrel, and gained 12 per cent. in the sale of it. What did he receive? 19. A man's income is $1500 a year; he saves 121 per cent. of it. How much does he spend? K* 163. To find what per cent. any number is of another given number, RULE. Annex two ciphers to the number whose per cent. is sought, and divide by the number of which it is sought. ART. 21. Obs. OBS. The numbers must have the same number of decimal places, or be of the same denomination. 20. What per cent. of $50 is $3? 50 ) 300 (6 300 Annexing two ciphers to the $3, and dividing by $50, gives 6 as the per cent. OBS. This rule is evidently the converse of the preceding. Thus 6 per cent. of $50 is $3. 50 X .06=3.00. 21. What per cent. of $150 is $4? 36. What per cent. of £9 10 s. is £2 4 s. 9 d.? What is the rule for finding what per cent. any number is of another given number?· SIMPLE INTEREST. SECTION XII. 164. INTEREST is a certain per cent. of a sum of money, paid for its use. OBS. The per cent. is called the rate, and is always reckoned per annum, which signifies by the year. 165. The sum on which the interest is computed is called the principal. The principal and interest, added together, is called the amount. 166. The rate per cent. is established by law, and varies in different states and countries. 167. The legal rate is 6 per cent. in the New England States, also in New Jersey, Pennsylvania, Delaware, Maryland, Virginia, North Carolina, Tennessee, Kentucky, Ohio, Indiana, Illinois, Missouri, Arkansas, District of Columbia, and on debts and judgments in favor of the United States; also in Canada, Nova Scotia, and Ireland.. 168. The legal rate is 7 per cent. in New York, Michigan, Wisconsin, Iowa, and South Carolina. 169. It is 8 per cent. in Georgia, Alabama, Mississippi, and Florida. 170. It is 5 per cent. in Louisiana, also in England and France. 171. RULE. Find the interest of one dollar for the time, and by this multiply the principal; Or remove the decimal point in the principal two places to the left, and multiply by one half of the number of months, and one sixtieth of the number of days. What is interest? What is the per cent. called? What is the meaning of per annum? What is the principal? What is the amount? How is the rate determined? What is the rule for casting interest? OBS. If the principal contain only dollars, point off two figures on the right for cents. It is evident that the interest of one dollar for twelve months, at 6 per cent., is six cents; for two months, or sixty days, one cent; and the interest of one dollar, for any number of months, is one cent. for every two months, or one half as many cents as there are months; and the interest of one dollar for one day is one sixtieth of a cent, or one sixth of a mill, and the interest of one dollar for any number of days is one sixth as many mills as there are days. 1. What is the interest of $1 for 1 year, 9 months, and 5 days? Interest for 1 year is = .06 66 "9 months is = .045 is = .000% .105 2. What is the interest of $1 for 3 years, 5 months, and 3 days? Interest for 3 years is.18 66 5 months is = .025 3 days is .000% .205% OBS. By the preceding rule, the interest for days is found for as many 360ths of one year's interest as there are days, which is evidently, or too much. When great accuracy is required, as many 365ths of one year's interest must be taken as there are days, or of the interest for days, found by the preceding rule, must be deducted. Some states require this deduction to be made. EXAMPLES. 3. What is the interest of $1 for 7 months and 9 days? 4. What is the interest of $1 for 10 months and 4 days? |