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

Example Input: Problem: a cat chases a rat 6 hours after the rat runs . cat takes 4 hours to reach the rat . if the average speed of the cat is 90 kmph , what s the average speed of the rat ?
Example Output: 36 kmph

Example Input: Problem: a hiker walking at a constant rate of 4 kilometers per hour is passed by a cyclist travelling in the same direction along the same path at a constant rate of 30 kilometers per hour . the cyclist stops and waits for the hiker 5 minutes after passing her while the hiker continues to walk at her constant rate . how many minutes must the cyclist wait until the hiker catches up ?
Example Output: 32.

Example Input: Problem: the ratio , by volume , of soap to alcohol to water in a certain solution is 6 : 30 : 90 . the solution will be altered so that the ratio of soap to alcohol is doubled while the ratio of soap to water is halved . if the altered solution will contain 150 cubic centimeters of alcohol , how many cubic centimeters of water will it contain ?
Example Output:
1800