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'.

Q: Problem: of 600 surveyed students , 20 % of those who read book a also read book b and 25 % of those who read book b also read book a . if each student read at least one of the books , what is the difference between the number of students who read only book a and the number of students who read only book b ? 
Options: a ) 20 , b ) 25 , c ) 30 , d ) 35 , e ) 75

A: e
****
Q: Problem: 120 students represent x percent of the boys at a school . if the boys at the school make up 30 % of the total school population of x students , what is x ? 
Options: a ) 120 , b ) 150 , c ) 180 , d ) 200 , e ) 250

A: d
****
Q: Problem: in a recent election , geoff received 0.5 percent of the 6,000 votes cast . to win the election , a candidate needed to receive more than x % of the vote . if geoff needed exactly 3,571 more votes to win the election , what is the value of x ? 
Options: a ) 50 , b ) 54 , c ) 56 , d ) 60 , e ) 63

A:
d
****