Two pipes can fill a tank in 10 hrs and 15 hrs. A drain pipe empties in 20 hrs. All three open, tank fills in:

A 8.57 hrs

B 10 hrs

C 12 hrs

D 15 hrs

✓ Correct Answer: Option C

1/10 + 1/15 - 1/20 = 6/60+4/60-3/60 = 7/60. Time ≈ 8.57hrs. Actually 60/7 = 8.57.

💡 Why is C) the correct answer?

The correct answer to the question "Two pipes can fill a tank in 10 hrs and 15 hrs. A drain pipe empties in 20 hrs. All three open, tank fills in:" is Option C: 12 hrs.

The other options — A) 8.57 hrs, B) 10 hrs, D) 15 hrs — are incorrect for this Mathematics question. As explained above: 1/10 + 1/15 - 1/20 = 6/60+4/60-3/60 = 7/60. Time ≈ 8.57hrs. Actually 60/7 = 8.57.

📚 About This Mathematics Practice Question

This 2-level Mathematics question from the Quantitative Reasoning topic is part of One Paper Preparation's free exam preparation library. Each question includes the correct answer and a detailed explanation to help you understand the underlying concept, not just memorize the answer.

How to use this page: Read the question above, consider all four options (A through D), then check the highlighted correct answer and explanation. For active timed practice, start a free Mathematics practice test or use flashcards for spaced repetition review.

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Two pipes can fill a tank in 10 hrs and 15 hrs. A drain pipe empties in 20 hrs. All three open, tank fills in:

✓ Correct Answer: Option C

📚 About This Mathematics Practice Question

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