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

Input: Consider 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 )

Output: 5 / 5

Input: Consider Input: Problem: 13 buckets of water fill a tank when the capacity of each bucket is 42 litres . how many buckets will be needed to fill the same tank , if the capacity of each bucket is 6 litres ?

Output: 91

Input: Consider Input: Problem: if n = 2 ^ 0.15 and n ^ b = 8 , b must equal
Output: 20