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 liters of a 40 % iodine solution need to be mixed with 35 liters of a 20 % iodine solution to create a 32 % iodine solution ? 
Options: a ) 35 , b ) 49 , c ) 100 , d ) 102 , e ) 140
[EX A]: d

[EX Q]: Problem: in a class , if 50 % of the boys were girls , then there would be 50 % more girls than boys . what percentage of the overall class is girls ? 
Options: a ) 25 % , b ) 33.33 % , c ) 40 % , d ) 20 % , e ) 10 %
[EX A]: d

[EX Q]: Problem: calculate how long it will take a swimmer to swim a distance of 8 km against the current of a river which flows at 1.4 km / hr , given that he can swim in still water at 3 km / h 
Options: a ) 20 seconds , b ) 3 , c ) 4 , d ) 1 , e ) 5
[EX A]:
e