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

Example Input: Problem: . 005 / ? = . 01
Example Output: . 5

Example Input: Problem: a cycle is bought for rs . 900 and sold for rs . 1080 , find the gain percent ?
Example Output: 20 %

Example Input: Problem: a certain sum is invested at simple interest at 18 % p . a . for two years instead of investing at 12 % p . a . for the same time period . therefore the interest received is more by rs . 840 . find the sum ?
Example Output:
7000