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

Example Input: Problem: a train 150 m long is running at a speed of 68 kmph . how long does it take to pass a man who is running at 8 kmph in the same direction as the train ?
Example Output: 9 sec

Example Input: Problem: how many multiples of 7 are there between 10 and 100 ( both are inclusive ) ?
Example Output: 13

Example Input: Problem: the average ( arithmetic mean ) of 7 , 8 , 10 and 11 equals the average of 2 , 9 , 13 , and
Example Output:
12