182 ARITHMETIC. 



3. What debt will be discharged in a year, or twelve 

 months, by paying il. the first month, 2L the second, 4I. 

 the third, and so on, each succeeding payment being double 

 the last J and what will the last payment be ? 



Ans. The debt is 4095I. and the last paym,^t 2C48I 



SIMPLE INTEREST/ 



Interest is the premium, allowed for the loan of 

 money* 



The sum lent is called the principal. 



The sum of the principal and interest is called the 

 amount. 



Interest is allowed at so much per cent, per atmum^ which 

 premium per cent, per annum y or interest of lool. for a 

 year, is called the rate of interest. 



Interest is of two sorts, simple and compound. 



Simple interest is that, which is allowed only for the 

 principal lent. 



Note. Commission, Brokerage, Insurance, Stocks,* 

 and, in general, whatever is at a certain rate, or sum per 

 cent, are calculated like Simple Interest. 



RULE.f 



1. Multiply the principal by the rate, and divide the 

 product by 100 ; and the quotient is the answer for one 

 year. 



2. Multiply 



* Stock is a general name for public funds, and capitals of trad- 

 ing companies, the shares of which are transferable from one per- 

 son to another. 



f The rule is evidently an application of Simple Proportion 

 and Practice. 



