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The table shows the results of a Mathematics test in a class

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The table shows the results of a Mathematics test in a class

by Max@Math Revolution » Fri Oct 18, 2019 1:42 am
[GMAT math practice question]

The table shows the results of a Mathematics test in a class. The test range of 20% of the students in that class is between 70~80. How many students are there in that class?

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A. 20
B. 23
C. 25
D. 26
E. 28
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by Max@Math Revolution » Sun Oct 20, 2019 5:50 pm
=>

If x is the number of students with scores between 70 and 80, then we have x/(x+20) = 20/100 or 100x = 20(x+20), and 100x = 20x+400.
Then we have 80x = 400.
So we have x = 5, and the total number of students is 5+20=25.

Therefore, C is the answer.
Answer: C
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by swerve » Wed Oct 23, 2019 6:05 am
Max@Math Revolution wrote:[GMAT math practice question]

The table shows the results of a Mathematics test in a class. The test range of 20% of the students in that class is between 70~80. How many students are there in that class?

Image

A. 20
B. 23
C. 25
D. 26
E. 28
\begin{align*}
\frac{x}{x}+20 &=\frac{1}{5} \\
5x&=x+20 \\
4x&=20 \\
x&=5.
\end{align*}

So, \(5+20=25\,\Rightarrow\) C
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