A university class is composed of \(x\) men and \(y\) women.

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A university class is composed of \(x\) men and \(y\) women. If 2 men and 13 women join the class, and one person is selected at random from the enlarged class, then the probability that a male is selected can be represented by

A. \(\frac{x}{y}\)
B. \(\frac{x}{x+y}\)
C. \(\frac{x+2}{y+13}\)
D. \(\frac{x+2}{x+y+13}\)
E. \(\frac{x+2}{x+y+15}\)

The OA is E

Source: Economist GMAT
Source: — Problem Solving |

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by Brent@GMATPrepNow » Tue Sep 10, 2019 5:24 am
swerve wrote:A university class is composed of \(x\) men and \(y\) women. If 2 men and 13 women join the class, and one person is selected at random from the enlarged class, then the probability that a male is selected can be represented by

A. \(\frac{x}{y}\)
B. \(\frac{x}{x+y}\)
C. \(\frac{x+2}{y+13}\)
D. \(\frac{x+2}{x+y+13}\)
E. \(\frac{x+2}{x+y+15}\)

The OA is E

Source: Economist GMAT
If 2 men join the class, then the total number of men = x+2
If 13 women join the class, then the total number of women = y+13
To, the TOTAL number of students = (x+2) + (y+13) = x + y + 15

P(male is selected) = (x+2)/(x + y + 15)

Answer: E

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Brent
Brent Hanneson - Creator of GMATPrepNow.com
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by ELatour » Thu Sep 12, 2019 9:59 am
The easiest solution is to assume that both x and y are 0. If 2 men and 13 women join the class, then the chance that a man will be chosen is 2/15.

Which answer choice gives you that?

Not A
Not B
Not C
Not D
But E (0+2 / 0+0+15) does.

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by Scott@TargetTestPrep » Tue Sep 17, 2019 8:40 am
swerve wrote:A university class is composed of \(x\) men and \(y\) women. If 2 men and 13 women join the class, and one person is selected at random from the enlarged class, then the probability that a male is selected can be represented by

A. \(\frac{x}{y}\)
B. \(\frac{x}{x+y}\)
C. \(\frac{x+2}{y+13}\)
D. \(\frac{x+2}{x+y+13}\)
E. \(\frac{x+2}{x+y+15}\)

The OA is E

Source: Economist GMAT
We are given that a university class is composed of x men and y women and that 2 men and 13 women join the class.

The number of men in the enlarged class is x + 2, and the total number of students in the enlarged class is x + y + 2 + 13.

Thus, the probability of selecting a man from the enlarged class is:

(x + 2)/(x + y + 15)

Answer: E

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