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: a man can row his boat with the stream at 18 km / h and against the stream in 8 km / h . the man ' s rate is ? 
Options: a ) 5 kmph , b ) 2 kmph , c ) 7 kmph , d ) 8 kmph , e ) 3 kmph
[EX A]: a

[EX Q]: Problem: a shopkeeper sold 50 articles at the cost price of 60 articles . then find the profit % or lost % 
Options: a ) 20 % , b ) 22 % , c ) 25 % , d ) 30 % , e ) 35 %
[EX A]: a

[EX Q]: Problem: in a certain boys camp , 20 % of the total boys are from school a and 30 % of those study science . if there are 49 boys in the camp that are from school a but do not study science then what is the total number of boys in the camp ? 
Options: a ) 70 , b ) 245 , c ) 150 , d ) 35 , e ) 350
[EX A]:
e