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

[EX Q]: Problem: of the seven - digit positive integers that have no digits equal to zero , how many have two digits that are equal to each other and the remaining digit different from the other two ?
[EX A]: 152409600

[EX Q]: Problem: a tyre has two punctures . the first puncture alone would have made the tyre flat in 9 minutes and the second alone would have done it in 6 minutes . if air leaks out at a constant rate , how long does it take both the punctures together to make it flat ?
[EX A]: 335 min

[EX Q]: Problem: a man spends 2 / 5 of his salary on house rent , 3 / 10 of his salary on food and 1 / 8 of his salary on convenience he has rs . 1400 left with him , find his expenditure on food and conveyance .
[EX A]:
1000