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

Input: Consider Input: Problem: one fast typist type some matter in 4 hrs and another slow typist type the same matter in 6 hrs . if both do combine in how much time they will take to finish .

Output: 2 hr 24 mins


Input: Consider Input: Problem: find the sum the difference between the compound and s . i . on a certain sum of money for 5 years at 20 % per annum is rs . 75 of money ?

Output: 1875


Input: Consider Input: Problem: how many figures are required for numbering the pages of a book containing 1000 pages ?


Output: 2893