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

[EX Q]: Problem: what is the value of x ^ 2 yz xyz ^ 2 , if x = 2 , y = 1 , and z = 1 ?
[EX A]: 6

[EX Q]: Problem: how many prime numbers are between 51 / 13 and 89 / 9 ?
[EX A]: 2

[EX Q]: Problem: 15 men can complete a work in 10 days while 20 boys can complete the same work in 15 days . how many days will 10 men and 10 boys together take to complete the same work
[EX A]:
10 days