RULES OF BUSINESS 321 



SIMPLE-INTEREST RULES 



4%. Multiply the principal by the number of days to 

 run, separate the right-hand figure from the product and 

 divide by 9. 



5%. Multiply by the number of days and divide by 72. 



6%. Multiply by the number of days, separate the 

 right-hand figure and divide by 6. 



8%. Multiply by the number of days and divide by 45. 



9%. Multiply by the number of days, separate the 

 right-hand figure and divide by 4. 



10%. Multiply by the number of days and divide 

 by 36. 



12%. Multiply by the number of days, separate the 

 right-hand figure and divide by 3. 



The following method of computing interest for short 

 terms is an accurate and speedy one: The interest on 

 any sum for 60 days at 6 per cent, can be found by draw- 

 ing a perpendicular line 2 places to the left of the deci- 

 mal point of the principal. The result will be the 

 interest in dollars and cents. Thus, the interest on 

 $2,035.45 for 60 days at 6% will be $20.35. 



DISCOUNT RATES 



The following table of equivalent discounts will be 

 found useful by those in whose business several dif- 

 ferent rates of discount are allowed from list prices: 



10 and 5 off- 14^% off 



IS and 5 off=19^% off 



20 and 5 off=24% off 



20 and 10 off=28% off 



25 and 10 off=32H% off 



30, 10, and 5 off =401/7% off 



40, 10, and 5 off=48y 10 % off 



50 and 10 off =55% off 



60, 10, and 5 off=65%% off 



70, 10, and 5 off=74%o% off 



