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

Example Input: Problem: what ratio must a shopkeeper mix peas and soybean of rs . 16 and rs . 25 / kg , as to obtain a mixture of rs . 21.50 ?
Example Output: 7 : 11

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

Example Input: Problem: 31 of the scientists that attended a certain workshop were wolf prize laureates , and 18 of these 31 were also nobel prize laureates . of the scientists that attended that workshop and had not received the wolf prize , the number of scientists that had received the nobel prize was 3 greater than the number of scientists that had not received the nobel prize . if 50 of the scientists attended that workshop , how many of them were nobel prize laureates ?
Example Output:
d ) 29