The task is to generate the correct answer for a given math problem.

Example 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 66 books in the special collection at that time , how many books of the special collection were loaned out during that month ?
Example Output: 45

Example Input: Problem: positive integer y is 50 percent of 25 percent of positive integer x , and y percent of x equals 100 . what is the value of y ?
Example Output: 125

Example Input: Problem: the average weight of 4 person ' s increases by 8.5 kg when a new person comes in place of one of them weighing 95 kg . what might be the weight of the new person ?
Example Output:
129 kg