What fraction of this year's graduating students

[Vizay K]

Can somebody explain the solution. Correct answer is C

Thanks

[RonPurewal]

hi -

since this problem contains nothing but text, kindly reproduce it as a forum post in text form and then we'll take a look at it.

policy here is that image files should be used only for those problems that require them (i.e., math problems with diagrams and/or complicated formulas that can't be rendered properly in the forum). not everyone who comes on here has the bandwidth to handle the image posting, so please post anything that can be posted in text form in text form.

thanks!

[Steve G]

What fraction of this year’s graduating students at a certain college are males?

(1) Of this year’s graduating students, 33 percent of the males and 20 percent of the females transferred from another college.
(2) Of this year’s graduating students, 25 percent transferred from another college.

Wow I couldn't get C. I got E as well. hmmm wonder what I'm missing.

[RonPurewal]

What fraction of this year’s graduating students at a certain college are males?

(1) Of this year’s graduating students, 33 percent of the males and 20 percent of the females transferred from another college.
(2) Of this year’s graduating students, 25 percent transferred from another college.

Wow I couldn't get C. I got E as well. hmmm wonder what I'm missing.

--

hopefully it's fairly clear, after a little reflection, that each of the individual statements is insufficient; they're merely statements about percentages / proportions of students who transferred from other colleges. that won't do to figure out percentages of the entire graduating class.
BUT:
let's say M is the # of males in the graduating class (total), and F is the # of females.
then
statement (1) says 0.33M + 0.20F were transfers;
statement (2) says 0.25(M + F) were transfers (i.e., 25% of everybody).

since both of these are the # of transfers, set them equal:
0.33M + 0.20F = 0.25M + 0.25F
0.08M = 0.05F
this gives you the ratio of males to females if you continue to solve (which, of course, you don't have to)

...but, if you have the ratio of m : f (and there's no third gender, hopefully) that's SUFFICIENT to find the percentages.

[Steve G]

Thanks Ron.

Solution makes sense. Should have looked harder to see that (1) and (2) are related to each other!