why it is 200 why not 80

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why it is 200 why not 80

by sana.noor » Sat Jun 08, 2013 11:30 pm
Of the 800 employees of company X, 70% have been with the company for at leat 10 years. if "y" of these long-term members were to retire and no other employee changes were to occur, what value of y would reduce the percent of long-term employees in the company to 60 percent?
a) 200
b) 160
c) 112
d) 80
e) 56

OA is A
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by vivekchandrams » Sun Jun 09, 2013 12:10 am
Hi sana.noor,

I guess this is the error you have done

(560 - y) / (800) = 60%, which would give y = 80

But, when you are subtracting the people those who are retiring, you have to remove them from the number of total employees too.

Hence, the denominator would be (800 - y)

Hence the equation would be

(560-y) / (800-y) = 60/100.


That would give y = 200

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by GMATGuruNY » Sun Jun 09, 2013 3:53 am
sana.noor wrote:Of the 800 employees of company X, 70% have been with the company for at least 10 years. if "y" of these long-term members were to retire and no other employee changes were to occur, what value of y would reduce the percent of long-term employees in the company to 60 percent?
a) 200
b) 160
c) 112
d) 80
e) 56

OA is A
Current long-term = .7(800) = 560.
We can plug in the answers for the value of y.
Given that every value in the problem (800, 70, 60) is a multiple of 10, the correct answer choice almost certainly is itself a multiple of 10.

Answer choice B: 160

After 160 retire:
Remaining long-term = 560-160 = 400.
Remaining total = 800-160 = 640.
Resulting percentage = 400/640 * 100 = 62.5%.
For the resulting percentage to decrease to 60%, more long-term employees must retire.

The correct answer is A.
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by fcabanski » Sun Jun 09, 2013 9:25 am
Plugging in is easier on this type of problem.
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