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

[EX Q]: Problem: 6 ) a marketing firm determined that , of 260 households surveyed , 80 used neither brand a nor brand b soap . 60 used only brand a soap and for every household that used both brands of soap , 3 used only brand b soap . how many of the 200 household surveyed used both brands of soap ?
[EX A]: c ) 30

[EX Q]: Problem: how many numbers between 200 and 600 are divisible by 4 , 5 and 6 ?
[EX A]: 6

[EX Q]: Problem: a man swims downstream 30 km and upstream 20 km taking 5 hours each time , what is the speed of the man in still water ?
[EX A]:
5