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: 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
d

Problem: at a particular graduation party with 300 guests , 70 % of the guests brought gifts , and 40 % of the female guests brought gifts . if 15 males did not bring gifts to the party , how many females did bring gifts ? 
Options: a ) 18 , b ) 28 , c ) 50 , d ) 68 , e ) 70
c

Problem: how long will a boy take to run round a square field of side 45 meters , if he runs at the rate of 9 km / hr ? 
Options: a ) 72 sec , b ) 45 sec , c ) 1 min , d ) 32 sec , e ) 25 sec

a