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

[EX Q]: Problem: how many zeroes are there at the end of the number n , if n = 100 ! + 200 ! ?
[EX A]: 2

[EX Q]: Problem: x varies inversely as square of y . given that y = 3 for x = 1 . the value of x for y = 9 will be equal to :
[EX A]: 1 / 9

[EX Q]: Problem: a man sitting in a train which is travelling at 64 kmph observes that a goods train travelling in a opposite direction , takes 18 seconds to pass him . if the goods train is 420 m long , find its speed .
[EX A]:
20