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'.

[Q]: Problem: i bought two books ; for rs . 600 . i sold one at a loss of 15 % and other at a gain of 19 % and then i found each book was sold at the same price . find the cost of the book sold at a loss ? 
Options: a ) 197 , b ) 280 , c ) 189 , d ) 278 , e ) 350
[A]: e


[Q]: Problem: at a particular graduation party with 220 guests , 70 % of the guests brought gifts , and 40 % of the female guests brought gifts . if 12 males did not bring gifts to the party , how many females did bring gifts ? 
Options: a ) 18 , b ) 36 , c ) 42 , d ) 68 , e ) 70
[A]: b


[Q]: Problem: a tradesman sold an article at a loss of 10 % . if the selling price had been increased by $ 50 , there would have been a gain of 10 % . what was the cost price of the article ? 
Options: a ) $ 150 , b ) $ 200 , c ) $ 250 , d ) $ 120 , e ) $ 100
[A]:
c