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: how many pounds of salt at 50 cents / lb must be mixed with 40 lbs of salt that costs 25 cents / lb so that a merchant will get 20 % profit by selling the mixture at 48 cents / lb ? 
Options: a ) 20 , b ) 15 , c ) 40 , d ) 60 , e ) 25
[EX A]: d

[EX Q]: Problem: what percent of 12.4 kg is 20 gms ? 
Options: a ) 25 , b ) 16 , c ) 18 , d ) 19 , e ) 17
[EX A]: b

[EX Q]: Problem: in a public show 75 % of the seats were filled . if there were 600 seats in the hall , how many seats were vacant ? 
Options: a ) 100 , b ) 110 , c ) 120 , d ) 140 , e ) 150
[EX A]:
e