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

[EX Q]: Problem: a and b can do a piece of work in 7 days . with the help of c they finish the work in 5 days . c alone can do that piece of work in ?
[EX A]: 30 days

[EX Q]: Problem: a train running at the speed of 40 km / hr crosses a pole in 9 seconds . what is the length of the train ?
[EX A]: 100 meter

[EX Q]: Problem: a box measuring 36 inches long by 45 inches wide by 18 inches deep is to be filled entirely with identical cubes . no space is to be left unfilled . what is the smallest number of cubes that can accomplish this objective ?
[EX A]:
40