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A shop hired new employees recently. The number of male emp

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by Max@Math Revolution » Tue Dec 03, 2019 12:23 am
[GMAT math practice question]

Some employees joined and left a company recently.  The number of male employees increased by 10% and the number of female employees decreased by 10%. As a result, the number of all employees increased by 10 individuals, which is a 2% increment. How many male and female employees are there after the recent hiring?

A. 280, 250
B. 300, 200
C. 330, 180
D. 340, 180
E. 350, 200
Last edited by Max@Math Revolution on Thu Dec 05, 2019 10:28 am, edited 1 time in total.
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Source: — Problem Solving |

by Max@Math Revolution » Thu Dec 05, 2019 12:04 am
=>

Assume m and f are the numbers of male and female employees before hiring, respectively.

We have (m + f)*(2/100) = 10 or m + f = 500, since the number of employees increased by 2%.

We have m(10/100) - f(10/100) = 10 or m - f = 100, since the number of male employees increased by 10% and the number of female employees decreased by 10%.

When we add two equations, we have (m + f) + (m - f) = 500 + 100, 2m = 600 or m = 300.
Then f = 500 - m = 200.
There are 1.1m = 330 male employees and 0.9f = 180 female employees.

Therefore, C is the answer.
Answer: C
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