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subhasis8877
- Senior | Next Rank: 100 Posts
- Posts: 77
- Joined: Tue Mar 10, 2009 3:10 am
Question: What fraction of the class are males?
Class total = Males (M) + Females(F)
We need to find M/(M+F)
Statement 1: 0.33M + 0.2F were transferred. But we have no idea what fraction of the class were transferred. Insufficient.
Statement 2: 25% of class total were transferred. We have no info on the ratio or proportion of males and females in the class. Insufficient.
Both statements together:
0.33M + 0.2F = 0.25(M+F)
0.33M - 0.25M = 0.25F - 0.2F
0.08M = 0.05F
M/F = 5/8
Using the ratio M/F, we can evaluate the fraction of the class that are males (you can essentially stop here since this is a DS problem):
M/(M+F) = 5/13. Sufficient.
Choose C.
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