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: what annual installment will discharge a debt of rs . 1428 due in 3 years at 12 % simple interest ? 
Options: a ) 315 , b ) 345 , c ) 425 , d ) 335 , e ) none of them
[EX A]: c

[EX Q]: Problem: in a certain pond , 80 fish were caught , tagged , and returned to the pond . a few days later , 50 fish were caught again , of which 2 were found to have been tagged . if the percent of tagged fish in the second catch approximates the percent of tagged fish in the pond , what is the approximate number of fish in the pond ? 
Options: a ) 400 , b ) 625 , c ) 1,250 , d ) 2,000 , e ) 10,000
[EX A]: d

[EX Q]: Problem: on a map , 3 centimeters represents 33 kilometers . two cities 209 kilometers apart would be separated on the map by how many centimeters ? 
Options: a ) 19 , b ) 7 , c ) 13 , d ) 110 , e ) 180
[EX A]:
a