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Three pipes A, B, C together fill a tank in 4 hours. A and B together take 6 hours, and B and C together take 8 hours. How long does B alone take?

Competition practicePipes & Cisterns

A12 h
B8 h
C14 h
D24 h

Step-by-Step Solution

C

= \frac{1}{4} - \frac{1}{6} = \frac{1}{12}

; A

= \frac{1}{4} - \frac{1}{8} = \frac{1}{8}

. B

= \frac{1}{4} - \frac{1}{12} - \frac{1}{8} = \frac{6 - 2 - 3}{24} = \frac{1}{24}

→ 24 h. (12 h is C; 8 h is A.)

Answer: D) 24 h

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