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

Example Input: Problem: two cubes have their volumes are in the ratio 1 : 27 . find the ratio of their surface area ?
Example Output: 1 : 9', 'd ) 2 : 7', 'e ) 3 : 11'

Example Input: Problem: if ( 5 ^ 9 ) ( 9 ^ 5 ) = 3 ( 15 ^ x ) , what is the value of x ?
Example Output: 9

Example Input: Problem: a train 300 m long is running with a speed of 68 kmph . in what time will it pass a man who is running at 8 kmph in the same direction in which the train is going ?
Example Output:
18 sec .