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: the cost price of a radio is rs . 2550 and it was sold for rs . 2130 , find the loss % ? 
Options: a ) 18 , b ) 10 , c ) 15 , d ) 66 , e ) 41
[EX A]: c

[EX Q]: Problem: in an office , 20 percent of the workers have at least 5 years of service , and a total of 16 workers have at least 10 years of service . if 90 percent of the workers have fewer than 10 years of service , how many of the workers have at least 5 but fewer than 10 years of service ? 
Options: a ) 32 , b ) 64 , c ) 50 , d ) 144 , e ) 160
[EX A]: a

[EX Q]: Problem: in a certain pond , 50 fish were caught , tagged , and returned to the pond . a few days later , 50 fish were caught again , of which 5 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 ) 500 , c ) 1,250 , d ) 2,500 , e ) 10,000
[EX A]:
b