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

[Q]: Problem: a and b can do a work in 5 days and 10 days respectively . a starts the work and b joins him after 2 days . in how many days can they complete the remaining work ?
[A]: 2


[Q]: Problem: the ratio of three numbers is 2 : 3 : 4 and their sum is 180 . the second number of the three numbers is ?
[A]: 60


[Q]: Problem: 27 is a perfect cube . when x is added to the prime factor of 27 , the result is a prime number . what is x ?
[A]:
8