244 WALL'S MANUAL 



A FEW SIMPLE AND USEFUL EULES. 



I. To calculate simple interest at six per cent 

 Multiply the dollars by half the number of months, 

 and the result will be the interest in cents. For odd 

 days, multiply the dollars by the whole number of 

 days, and divide by sixty the result will be the 

 interest in cents. 



For any other rate of interest, as seven or eight per 

 cent. Multiply the dollars by the rate per cent. the 

 result will be the interest for one year in cents. This, 

 divided by twelve, is the interest for one month. The 

 interest for one month, divided by thirty, gives the 

 interest for one day. From these, the interest for 

 any period may be calculated. 



II. To determine how many bushels a given space 

 will hold. Multiply the length, width and depth, 

 measured in feet. This will give the contents in 

 cubic feet. Now, as there are two thousand one 

 hundred and fifty cubic inches in a bushel and one 

 thousand seven hundred and twenty- eight in a foot, 

 these numbers stand (nearly) to each other as four to 

 five. Hence, multiply the cubic feet of the given 

 space by four and divide by five, will give the bushels 

 (very nearly). 



Example. A crib eight feet long, five feet wide, 

 and six feet deep, contains (8x5x6) = 240 cubic 

 feet, then 240 x 4 = 960 cubic feet, which, divided by 

 five, gives one hundred and ninety- two bushels as the 

 contents of the crib, very nearly. 



