In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

[EX Q]: Problem: the price of a book is increased from $ 300 to $ 480 . what is the % of increase in its price ? 
Options: a ) 10 % , b ) 20 % , c ) 40 % , d ) 50 % , e ) 60 %
[EX A]: e

[EX Q]: Problem: an agent , gets a commission of 4 % on the sales of cloth . if on a certain day , he gets rs . 12.50 as commission , the cloth sold through him on that day is worth 
Options: a ) 312 , b ) 500 , c ) 887 , d ) 299 , e ) 132
[EX A]: a

[EX Q]: Problem: a sum of money at simple interest amounts to rs . 815 in 3 years and to rs . 864 in 4 years . the sum is : 
Options: a ) s . 650 , b ) s . 690 , c ) s . 668 , d ) s . 700 , e ) s . 760
[EX A]:
c