The federal arithmetic; or, a compendium of the most useful rules of that science, adapted to the currency of the United States, for the use of schools and private persons

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1808 Excerpt: ... of Three Inverse teaches, by having three numbers given, to find a fourth, bearing the same proportion to the second, as the first does to the third. If more require less, or less require more, the question belongs to the Single Rule of Three Inverse. When more requires less, the third term is greater 'than the first, and requires the fourth term to be less than the second. And when less requires more, the third term is less than the lirst,and requires the fourth term to be greater than the second. 'RULE. State and reduce the terms, as in the Ru'e of Three Direct.; then multiply the firit and second terms together, divide the product by the third, and the quotient will be the answer, in the same denomination with the second term. EXAMPLES. 1. If a field will feed 6 cows 12 weeks; how long will it feed 24 cows. cows.-weens, covu. 6: 12:: 24 24)72(3 weeks, Answer. 72 2. Lent a friend 292 dollars, for 6 months; sometime afterwards he lent me 806 dollars; how long-may I keep it, to balance the favor? dol. mo. dot. As 292: 6:: 806 6.806)1752(2 months. 1612 140 28 1120 280..'. 806)3920(4f » days. 3224 Answer, 2 months, 4f days, 151. 4. If 21 men can do a piece of work in 85 days; how many men will do it in 51 days? Answer, 35 men. 5. Lent 46 dollars, 50 cents, for 320 days-r after which,agreed to receive a sum large enough to balance the favor in 100 days; what must the sum be? Answer, 148 dollars, 80 cents. 6. If the 3 penny white loaf weigh 14oz. when wheat is sold for 6. lOd. per bushel; what ought it to weigh when wheat is sold for 4. 9d. per bushel I Answer, 20oz. 2pwt. 19%$gr. 7. There is a cistern, having one pipe which will empty it in 10 hours; how many pipes of the same capacity will empty it in 24 minutes.? b. p m, pipet. As 10: 1:: 24: 25 Answer...