general math MCQ #315

Two pipes can fill an empty tank in 10 and 15 hrs. respectively. If waste pipe C is opened both A and B together can fill the tank in 5 hours. The waste pipe can empty the full tank in:

general math MCQ #315

  1. Question 1

    Q1. Two pipes can fill an empty tank in 10 and 15 hrs. respectively. If waste pipe C is opened both A and B together can fill the tank in 5 hours. The waste pipe can empty the full tank in:

    • A) 30 hrs.
    • B) 50hrs
    • C) 60 hrs.
    • D) 40 hrs.

    Answer: 30 hrs.

    Explanation: A and B together fill 1/10+1/15 = 1/6 per hour; with waste pipe open net rate = 1/5; waste pipe drains 1/5−1/6.