TASK DEFINITION: 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'.
PROBLEM: Problem: in a certain pond , 40 fish were caught , tagged , and returned to the pond . a few days later , 40 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 ) 1000 , b ) 625 , c ) 1,250 , d ) 2,500 , e ) 10,000

SOLUTION: a

PROBLEM: Problem: an error 6 % in excess is made while measuring the side of a square . the percentage of error in the calculated area of the square is : 
Options: a ) 12.36 , b ) 8.36 , c ) 9.36 , d ) 10.36 , e ) 11.36

SOLUTION: a

PROBLEM: Problem: two numbers are less than a third number by 30 % and 37 % . how much percent is the second number is less than the first ? 
Options: a ) 10 % , b ) 15 % , c ) 20 % , d ) 25 % , e ) 30 %

SOLUTION:
a