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

[EX Q]: Problem: excluding stoppages , the average speed of a bus is 60 km / hr and including stoppages , the average speed of the bus is 40 km / hr . for how many minutes does the bus stop per hour ?
[EX A]: 20 min

[EX Q]: Problem: when positive integer n is divided by 5 , the remainder is 1 . when n is divided by 7 , the remainder is 3 . what is the smallest positive integer k such that k + n is a multiple of 40 .
[EX A]: 7

[EX Q]: Problem: 6 women can do 75 units of work in 8 days by working 5 hrs / day . in how many days can 4 women do 30 units of work by working 8 hrs / day ?
[EX A]:
3 days