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- Write the ratio clearly.
- Find the common multiplier.
- Apply it to the missing term.
Correct Answer: C
Correct Answer: C
Method / Topic: Ratio and Proportion
The answer keeps the ratio proportional.
Short Explanation
Detailed Explanation
Correct Answer: C
Method / Topic: Ratio and Proportion
<table cellspacing="0" style="border-collapse:collapse; height:20px; width:85px">
<tbody>
<tr>
<td style="background-color:#c0e6f5; border-bottom:1px solid #44b3e1; border-left:none; border-right:none; border-top:1px solid #44b3e1; height:20px; vertical-align:top; white-space:normal; width:85px"><span style="color:#000000">Let the numbers of boys and girls be 7x and 5x. Their difference is 2x, and this difference is given as 18. Therefore, 2x=18 and x=9. Boys=7×9=63 and girls=5×9=45. Hence, total students=63+45=108. The key step is to use the difference between the ratio terms rather than adding the terms at the beginning. Once the value of one ratio unit is found, both groups can be calculated directly.</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
- Write the ratio clearly.
- Find the common multiplier.
- Apply it to the missing term.
The ratio of boys to girls in a class is 7:5. If there are 18 more boys than girls, find the total number of students.
Explanation
Correct Answer: C
Method / Topic: Ratio and Proportion
The answer keeps the ratio proportional.
Short Explanation
Detailed Explanation
Correct Answer: C
Method / Topic: Ratio and Proportion
<table cellspacing="0" style="border-collapse:collapse; height:20px; width:85px">
<tbody>
<tr>
<td style="background-color:#c0e6f5; border-bottom:1px solid #44b3e1; border-left:none; border-right:none; border-top:1px solid #44b3e1; height:20px; vertical-align:top; white-space:normal; width:85px"><span style="color:#000000">Let the numbers of boys and girls be 7x and 5x. Their difference is 2x, and this difference is given as 18. Therefore, 2x=18 and x=9. Boys=7×9=63 and girls=5×9=45. Hence, total students=63+45=108. The key step is to use the difference between the ratio terms rather than adding the terms at the beginning. Once the value of one ratio unit is found, both groups can be calculated directly.</span></td>
</tr>
</tbody>
</table>
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