Pipe A, B and C together can fill a tank in 20 minutes. Pipe B and C together can fill the same tank in 30 minutes. Pipe C and A together can fill the same tank in 24 minutes. In how much time (in minutes) pipe B alone can fill the tank?
Show answer & explanation
Correct answer: C
Explanation
Given:
A + B + C = 20 minutes
B + C = 30 minutes
C + A = 24 minutes
Rate of A + B + C = 1/20
Rate of B + C = 1/30
Rate of A = (1/20 − 1/30)
= (3 − 2)/60
= 1/60
C + A = 1/24
C + 1/60 = 1/24
C = (1/24 − 1/60)
= (5 − 2)/120
= 1/40
B + C = 1/30
B + 1/40 = 1/30
B = (1/30 − 1/40)
= (4 − 3)/120
= 1/120
Time = 120 minutes