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- Find each pipe's rate.
- Add filling rates and subtract emptying rates.
- Invert the net rate to get time.
Correct Answer: A
Correct Answer: A
Method / Topic: Pipes and Cisterns
The answer uses the net filling rate.
Short Explanation
Detailed Explanation
Correct Answer: A
Method / Topic: Pipes and Cisterns
<table cellspacing="0" style="border-collapse:collapse; height:20px; width:85px">
<tbody>
<tr>
<td style="border-bottom:none; border-left:none; border-right:none; border-top:none; height:20px; vertical-align:top; white-space:normal; width:85px"><span style="color:#000000">Net rate=1/12-1/24=1/24 tank per hour. In 6 hours, filled fraction=6/24=1/4.</span></td>
</tr>
</tbody>
</table>
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Learn + Solve: Shortcut, Trap & Fast Route Click to view shortcut, steps, and common mistake
Shortcut used, common trap, and the fastest solving route
- Find each pipe's rate.
- Add filling rates and subtract emptying rates.
- Invert the net rate to get time.
An inlet fills a tank in 12 hours and an outlet empties it in 24 hours. What fraction of the tank is filled in 6 hours when both are open?
Explanation
Correct Answer: A
Method / Topic: Pipes and Cisterns
The answer uses the net filling rate.
Short Explanation
Detailed Explanation
Correct Answer: A
Method / Topic: Pipes and Cisterns
<table cellspacing="0" style="border-collapse:collapse; height:20px; width:85px">
<tbody>
<tr>
<td style="border-bottom:none; border-left:none; border-right:none; border-top:none; height:20px; vertical-align:top; white-space:normal; width:85px"><span style="color:#000000">Net rate=1/12-1/24=1/24 tank per hour. In 6 hours, filled fraction=6/24=1/4.</span></td>
</tr>
</tbody>
</table>
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