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- Take total work as 1 or LCM.
- Find each one-day work rate.
- Combine rates as required.
Correct Answer: B
Correct Answer: B
Method / Topic: Time and Work
The answer is based on combined work rates.
Short Explanation
Detailed Explanation
Correct Answer: B
Method / Topic: Time and Work
<table cellspacing="0" style="border-collapse:collapse; 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">A's one-day work is 1/20 and B's is 1/30. Together, they do 1/20+1/30 = 3/60+2/60 = 5/60 = 1/12 of the job per day. Therefore, they need 12 days.</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
- Take total work as 1 or LCM.
- Find each one-day work rate.
- Combine rates as required.
A can complete a job in 20 days and B can complete it in 30 days. In how many days can they complete it together?
Explanation
Correct Answer: B
Method / Topic: Time and Work
The answer is based on combined work rates.
Short Explanation
Detailed Explanation
Correct Answer: B
Method / Topic: Time and Work
<table cellspacing="0" style="border-collapse:collapse; 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">A's one-day work is 1/20 and B's is 1/30. Together, they do 1/20+1/30 = 3/60+2/60 = 5/60 = 1/12 of the job per day. Therefore, they need 12 days.</td>
</tr>
</tbody>
</table>
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