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- Identify the base.
- Convert percent to fraction/decimal.
- Calculate and match options.
Correct Answer: B
Correct Answer: B
Method / Topic: Percentage
The answer uses the correct base for the percentage calculation.
Short Explanation
Detailed Explanation
Correct Answer: B
Method / Topic: Percentage
<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:bottom; white-space:normal; width:85px"><span style="color:#000000">QUESTION:<br />
A number is increased by 20% and becomes 540. What was the original number?<br />
<br />
<br />
After a 20% increase, the final value equals 120% of the original value.<br />
<br />
<br />
Original value = 540 × 100 / 120 = 450.<br />
<br />
CHECK:<br />
Twenty percent of 450 is 90, and 450 + 90 = 540.<br />
<br />
EXAM TIP:<br />
Identify the base quantity before applying any percentage. For successive changes, use multiplication factors to avoid sign and base errors.<br />
<br />
<br />
Do not subtract 20% of 540, because 540 is the increased value, not the base.<br />
<br />
REAL-LIFE APPLICATION:<br />
Reverse percentages help recover an original salary, price, or population after a reported increase.<br />
<br />
<br />
Original number = 540 / 1.20 = 450.</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
- Identify the base.
- Convert percent to fraction/decimal.
- Calculate and match options.
A number is increased by 20% and becomes 540. What was the original number?
Explanation
Correct Answer: B
Method / Topic: Percentage
The answer uses the correct base for the percentage calculation.
Short Explanation
Detailed Explanation
Correct Answer: B
Method / Topic: Percentage
<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:bottom; white-space:normal; width:85px"><span style="color:#000000">QUESTION:<br />
A number is increased by 20% and becomes 540. What was the original number?<br />
<br />
<br />
After a 20% increase, the final value equals 120% of the original value.<br />
<br />
<br />
Original value = 540 × 100 / 120 = 450.<br />
<br />
CHECK:<br />
Twenty percent of 450 is 90, and 450 + 90 = 540.<br />
<br />
EXAM TIP:<br />
Identify the base quantity before applying any percentage. For successive changes, use multiplication factors to avoid sign and base errors.<br />
<br />
<br />
Do not subtract 20% of 540, because 540 is the increased value, not the base.<br />
<br />
REAL-LIFE APPLICATION:<br />
Reverse percentages help recover an original salary, price, or population after a reported increase.<br />
<br />
<br />
Original number = 540 / 1.20 = 450.</span></td>
</tr>
</tbody>
</table>
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