arnaudl wrote:
I got the spy girl question mentioned at the top no later than this afternoon on a gmat prep test.
I answered E but the correct answer given is C. Can someone help please ?
What fraction of this year's graduating students at a certain college are males?
a. Of this year's graduating students, 33 percent of the males and 20 percent of the females transferred from another college.
b. Of this year's graduating students, 25 percent transferred from another college.
From S2, if we have m males and f females, (m+f)/4 transfered from another college. From S1, m/3 + f/5 transferred from another college. These are equal:
(m + f)/4 = m/3 + f/5
15m + 15f = 20m + 12f
5m = 3f
m/f = 3/5
so the ratio of men to women is 3 to 5, and 3/8 of all students are male.
Alternatively you could recognize that the two statements combined give us a weighted average situation; from the first statement we know the % from each group who transferred, and from the second statement we know the % of the two groups combined who transferred, from which it is always possible to find the ratio of the two groups; there's no need to calculate anything here.
I'm not sure why the answer is indicated as E in the post at the beginning of this thread.
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