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

Example Input: Problem: jack and jill are marathon runners . jack can finish a marathon ( 42 km ) in 7 hours and jill can run a marathon in 4.2 hours . what is the ratio of their average running speed ? ( jack : jill )
Example Output: 5 / 5

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: if the length of the longest chord of a certain circle is 10 , what is the radius of that certain circle ?
Example Output:
5', 'c ) 10', 'd ) 15', 'e ) 20'