Math problems from the *free* official practice tests and
problems from mba.com
Jellie
 
 

In a sample of college students, 40 percent

by Jellie Sat Sep 06, 2008 7:52 pm

In a sample of college students, 40 percent are third-year students and 70 percent are not second-year students. What fraction of those students who are not third-year students are second-year students?
(A) 43
(B) 32
(C) 74
(D) 21
(E) 73

I started the problem by setting up a double set diagram with the arrangement (second year/non second year in the column and third year/not third year in the row)..I got stuck after that part though. Any help would be appreciated
Dan
 
 

Not much help from me

by Dan Sun Sep 07, 2008 3:45 am

I can't seem to get any of the answer choices to match up with my solution:

40 are 3rd year = 60 are not 3rd year
70 are not 2nd year = 70 are 1st, 3rd, 4th year
We know 40 are 3rd year, so 1st and 4th add to 30, 30 is left for 2nd year
Or, as the question stem indicates, 70 are not 2nd year, so 30 must be 2nd year

I get 30/60
RonPurewal
Students
 
Posts: 19744
Joined: Tue Aug 14, 2007 8:23 am
 

Re: Not much help from me

by RonPurewal Mon Sep 29, 2008 5:43 am

Dan Wrote:I can't seem to get any of the answer choices to match up with my solution:

40 are 3rd year = 60 are not 3rd year
70 are not 2nd year = 70 are 1st, 3rd, 4th year
We know 40 are 3rd year, so 1st and 4th add to 30, 30 is left for 2nd year
Or, as the question stem indicates, 70 are not 2nd year, so 30 must be 2nd year

I get 30/60


yeah, i get 30/60 too.
you don't have to do quite as much calculation, though, given the current information in the problem; you could just do this:
40 percent are third-year --> 60 percent are not third-year.
70 percent are not second-year --> 30 percent are second-year.
taking the problem statement as written, then, we'd have 30/60, or 50%.

therefore, something must be wrong with the transcription of the problem.
in fact, there's definitely more than one thing wrong with this problem - either that or it's not really a gmatprep problem.
* genuine gmatprep problems, after all, ALWAYS give answer choices in numerical order, with the only exception being cases in which that numerical order would give the problem away (e.g., "which of the following numbers is 3rd biggest?" for a bunch of fractions or decimals).
* also, the problem statement purportedly refers to "fractions", but the given answer choices clearly aren't fractions. they look like percentages - but they're weird percentages, too.

where'd you get this problem? could you double- and triple-check it, please?
thanks.
gupta.ab
 
Posts: 5
Joined: Sat Jul 26, 2008 2:54 am
 

Re: In a sample of college students, 40 percent

by gupta.ab Tue Sep 22, 2009 2:07 am

This is a GMAT Paper Based Test problem. is the question flawed??
RonPurewal
Students
 
Posts: 19744
Joined: Tue Aug 14, 2007 8:23 am
 

Re: In a sample of college students, 40 percent

by RonPurewal Sat Sep 26, 2009 3:13 am

gupta.ab Wrote:This is a GMAT Paper Based Test problem. is the question flawed??


has it been transcribed correctly?

verbatim?

FROM THE ORIGINAL SOURCE? (you shouldn't place much trust in problems that have come from second- or thirdhand internet sources)
andspeed2
Students
 
Posts: 2
Joined: Wed Dec 31, 1969 8:00 pm
 

Re: In a sample of college students, 40 percent

by andspeed2 Tue Jun 21, 2011 11:39 pm

The answer choices have been copied wrongly. The correct choices are:

(A) 3/4
(B) 2/3
(C) 4/7
(D) 1/2
(E) 3/7
RonPurewal
Students
 
Posts: 19744
Joined: Tue Aug 14, 2007 8:23 am
 

Re: In a sample of college students, 40 percent

by RonPurewal Wed Jun 29, 2011 6:03 am

gupta.ab Wrote:This is a GMAT Paper Based Test problem. is the question flawed??


it's pretty obviously flawed, as 43, 32, 74, 21, and 73 are not fractions.

The answer choices have been copied wrongly. The correct choices are:

(A) 3/4
(B) 2/3
(C) 4/7
(D) 1/2
(E) 3/7


there we go. our answer from above is in here.