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: what annual installment will discharge a debt of rs . 1428 due in 3 years at 12 % simple interest ? 
Options: a ) 315 , b ) 345 , c ) 425 , d ) 335 , e ) none of them
[EX A]: c

[EX Q]: Problem: the salary of a person was reduced by 15 % . by what percent should his reduced salary be raised so as to bring it at par with his original salary ? 
Options: a ) 10 % , b ) 17.6 % , c ) 13.7 % , d ) 15.1 % , e ) 12.3 %
[EX A]: b

[EX Q]: Problem: a and b started a business in partnership investing rs . 20000 and rs . 15000 respectively . after 6 months , c joined them with rs . 20000 . what will be b ' s share in the total profit of rs . 25000 earned at the end of 2 years from the starting of the business ? 
Options: a ) rs . 7500 , b ) rs . 9000 , c ) rs . 9500 , d ) rs . 10,000 , e ) none
[EX A]:
a