INTEREST. 



TABLE, 



Showing the Simple Interest of One Pound for any Number of Days, at 5 j*er cent 



per Annum. 



Ex. 1. What is the interest of 250/. 

 for 63 days ? 



.0086301 X 250 = 2f. 3*. If d. 

 The interest for any number of days, 

 not specified in the table, may be easily 

 found, by adding two of the numbers 

 contained in it. 



Ex. 2. What is the interest of 1 15Z. for 

 237 days? 



The interest of ll. for 200 days is 



.0273972, and for 37 days .0050684, 



which added together make 0324656; 



therefore, 



.0324656 x 115 = 3/. Us. Sd. = the 



interest required. 



By the act of 12 Anne, no person is to 

 take for the loan of money, above 51. for 

 the interest of 100/. for a year; and all 

 notes, bonds, or other contracts made for 

 money at a greater rate of interest, are to 

 be void, and the offender to forfeit treble 

 the value. 



ISTTEREST, compound, is allowing inter- 

 est upon interest, or adding the interest 

 as it becomes due to its principal, and 

 considering the whole as a new principal, 

 bearing interest at the same rate as be- 



fore. Let r now represent the amount of 



one pound in one year, that is, principal 



and interest; let n = the number of years; 



p = the principal; a = the amount. Then 



1 : r : : r : r 2 the amount of ll. in 2 years, 



1 : r : : r* : r3 the amount of ll. in 3 years, 



1 : r : : r3 : r* the amount of I/, in 4 years, 



&c. 



Whence it appears, that r raised to the 

 power whose exponent is the given num- 

 ber of years, or r, will be the amount of 

 ll. in those years ; and as 



ll. : r : : p : a 



from which the following theorems are 

 easily deduced, viz. if the principal, time, 

 and rate of interest, are given, to find the 

 amount. 



Theo. 1. p X r* as a 

 If the amount, time, and rate, are given, 

 to find the principal ? 



. 2. =,. 



If the principal, amount, and time, are 



given, to find the rate? 



n nl a 

 Theo. 3. J -=?' 





