Multiple choice

Pipe A can fill a tank in 6 hours. Pipe B can fill the same tank in 8 hours. Pipe A , B and C can fill the tank in 12 hours, then which of the statement is true for the pipe C?

  1. It can fill the tank in 4 hours 40 minutes

  2. It can empty the tank in 4 hours 40 minutes

  3. It can empty the tank in 4 hours 48 minutes

  4. It can fill the tank in 4 hours 48 minutes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A's rate = 1/6, B's rate = 1/8. Combined A+B = 7/24. With A+B+C = 1/12, C's rate = 1/12 - 7/24 = -5/24 (negative means emptying). Time to empty = 24/5 = 4.8 hours = 4h 48m.

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