Pipe A can fill up a tank in 40 minutes and pipe B can fill up the same tank in 30 minutes, how many minutes will it take for the two pipes together to fill up the tank?

A 10

B 15

C 17(1/7)

D 18(4/7)

Correct Answer: Option C

pipe A can fill up 1/40 part of the tank in 1 minute

pipe B can fill up 1/30 part of tha tank in 1 minute

together the can fiil = (1/40 + 1/30) = 7/120 part in 1 minute

7/120 part in 1 minute

1 or full part = 120/7 minute = 17 (1/7) minute