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: if 40 % of a number is greater than 80 % of 5 by 2 , what is the number ? 
Options: a ) 3 , b ) 15 , c ) 20 , d ) 2 , e ) 5
[EX A]: b

[EX Q]: Problem: a grocer has 400 pounds of coffee in stock , 25 percent of which is decaffeinated . if the grocer buys another 100 pounds of coffee of which 60 percent is decaffeinated , what percent , by weight , of the grocer ’ s stock of coffee is decaffeinated ? 
Options: a ) 28 % , b ) 30 % , c ) 32 % , d ) 34 % , e ) 40 %
[EX A]: c

[EX Q]: Problem: the present population of a town is 500 . population increase rate is 10 % p . a . find the population of town before 2 years ? 
Options: a ) 512 , b ) 615 , c ) 810 , d ) 413 , e ) 123
[EX A]:
d