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

Input: Consider Input: Problem: a cistern 5 m long and 4 m wide contains water up to a depth of 1 m 25 cm . the total area of the wet surface is :

Output: 42.5 m 2

Input: Consider Input: Problem: a man is 28 years older than his son . in two years , his age will be twice the age of his son . the present age of the son is ?

Output: 26

Input: Consider Input: Problem: two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds . the ratio of their speeds is :
Output: 3 / 2 .