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'.

Input: Consider Input: Problem: a particular library has 75 books in a special collection , all of which were in the library at the beginning of the month . these book are occasionally loaned out through an inter - library program . if , by the end of the month , 80 percent of books that were loaned out are returned and there are 67 books in the special collection at that time , how many books of the special collection were loaned out during that month ? 
Options: a ) 20 , b ) 30 , c ) 35 , d ) 40 , e ) 55

Output: d


Input: Consider Input: Problem: the salary of a person was reduced by 10 % . by what percent should his reduced salary be raised so as to bring it at par with his original salary ? 
Options: a ) 10 % , b ) 11 1 / 9 % , c ) 13 2 / 7 % , d ) 15 3 / 11 % , e ) 12 1 / 3 %

Output: b


Input: Consider Input: Problem: a number increased by 30 % gives 780 . the number is 
Options: a ) 250 , b ) 400 , c ) 450 , d ) 600 , e ) 520


Output: d