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 = 70 ! + 140 ! ?
[EX A]: 16

[EX Q]: Problem: a man purchased earphone on friday . but he forgot how much it cost . the data he have are mean expenditure of all 7 days is 500 . expenditure on mon , tue , wed , thurs , sat , sun are 450600 , 400500 , 550300 . on friday he purchased 3 things one earphone , one pen and one notebook . pen cost 30 and notebook cost 50 . then what is cost of earphone ?
[EX A]: 620

[EX Q]: Problem: pipe a can fill a tank in 6 hours . due to a leak at the bottom , it takes 12 hours for the pipe a to fill the tank . in what time can the leak alone empty the full tank ?
[EX A]:
1