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: in a restaurant , the profit is 120 % of the cost . if the cost increases by 12 % but the selling price remains constant , approximately what percentage of the selling price is the profit ? 
Options: a ) 30 % , b ) 49 % , c ) 90 % , d ) 100 % , e ) none of these
[EX A]: b

[EX Q]: Problem: the owner of a furniture shop charges his customer 25 % more than the cost price . if a customer paid rs . 8340 for a computer table , then what was the cost price of the computer table ? 
Options: a ) rs . 6672 , b ) rs . 6727 , c ) rs . 6908 , d ) rs . 6725 , e ) rs . 6728
[EX A]: a

[EX Q]: Problem: a chemist mixes one liter of pure water with x liters of a 45 % salt solution , and the resulting mixture is a 15 % salt solution . what is the value of x ? 
Options: a ) 1 / 4 , b ) 1 / 3 , c ) 1 / 2 , d ) 1 , e ) 3
[EX A]:
c