Question

Two pipes A and B can separately fill a cistern in 24
and 32 minutes respectively. They started to fill a
cistern together, but B is turned off after few minutes
and A fills the rest of the cistern. If total time taken is 18
minutes, after how many minutes is tap B turned off?
A) 10 B) 14 C) 4 D) 8

Answer 1

Let the volume of cistern be V and time when B turned off be t min
For every minute before t, the cistern is filled up at rate of (V/24 + V/32)
For every minute from t, the cistern is filled up at rate of V/24
t(V/24 + V/32) + V(18-t)/24 = V
Solve for t

Answer 2

t/24 + t/32 + (18-t)/24 = 1
t = 8 minutes
so answer is D) 8minutes

Answer 3

ok @M.Manasa

Answer 4

right @Kira_Yamato

Answer 5

right @ajprincess

Answer 6

am i right? @jiteshmeghwal9

Answer 7

yes @ @mayankdevnani :)

Answer 8

thnx.. @jiteshmeghwal9

Answer 9

yw :)