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: an agent , gets a commission of 2.5 % on the sales of cloth . if on a certain day , he gets rs . 21 as commission , the cloth sold through him on that day is worth 
Options: a ) 333 , b ) 500 , c ) 840 , d ) 299 , e ) 132
[EX A]: c

[EX Q]: Problem: a person buys an article at rs . 400 . at what price should he sell the article so as to make a profit of 40 % ? 
Options: a ) 600 , b ) 277 , c ) 560 , d ) 261 , e ) 281
[EX A]: c

[EX Q]: Problem: at what rate percent per annum will the simple interest on a sum of money be 6 / 5 of the amount in 10 years ? 
Options: a ) 4 % , b ) 7 % , c ) 9 % , d ) 3 % , e ) 12 %
[EX A]:
e