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

Example Input: Problem: what is the probability of getting a queen or spade from a set of cards ?
Example Output: 4 / 13

Example Input: Problem: in one alloy there is 12 % chromium while in another alloy it is 8 % . 35 kg of the first alloy was melted together with 40 kg of the second one to form a third alloy . find the percentage of chromium in the new alloy .
Example Output: 9.75 %

Example Input: Problem: how many seconds will a train 100 meters long take to cross a bridge 140 meters long if the speed of the train is 36 kmph ?
Example Output:
24