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Students in the city

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Students in the city

by metallicafan » Fri Mar 02, 2012 10:53 am
Are at least 20 percent of the students in City X employed?

(1) In City X, 16.8 percent of the population consists of
students.
(2) In City X, 35 percent of the students 25 years of age
and older are employed and 20 percent of the students
younger than 25 years of age are employed.

Common sense tells me the answer, and I am right!
However, I would like to know if someone can show it using math or algebra.
Thanks!

OA: _B_

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by kul512 » Fri Mar 02, 2012 11:26 am
Mettalicafan, you are correct,common sense should tell the answer at first glance. But as you want the mathematical answer , here it is-

1. Option A alone is not sufficient because it didnt even mention the employment term.

2. suppose there are X student of 25 years age or older, and Y student younger than 25 years.
so

Total employed student=35% of X+ 20% of Y= 0.35X+0.2Y..........................(1)

total student= X+Y
question asks if employed students>= 20% of (X+Y)

from equation (1)

if
0.35X+0.2Y>=0.2(X+Y)
0.35X>=0.2X
0.35>=0.2

which is always right. So B is sufficient.
Sometimes there is very fine line between right and wrong: perspective.
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