French or German

This topic has expert replies
User avatar
Master | Next Rank: 500 Posts
Posts: 425
Joined: Wed Dec 08, 2010 9:00 am
Thanked: 56 times
Followed by:7 members
GMAT Score:690

French or German

by LalaB » Sun Oct 23, 2011 9:20 am
Many of the students at the International School speak French or German or both. Among the students who
speak French, four times as many speak German as don't. In addition, 1/6 of the students who don't speak
German do speak French. What fraction of the students speak German?
(1) Exactly 60 students speak French and German.
(2) Exactly 75 students speak neither French nor German.
Source: — Data Sufficiency |

User avatar
Master | Next Rank: 500 Posts
Posts: 496
Joined: Tue Jun 07, 2011 5:34 am
Thanked: 38 times
Followed by:1 members

by sl750 » Mon Oct 24, 2011 9:57 am
LalaB wrote:Many of the students at the International School speak French or German or both. Among the students who
speak French, four times as many speak German as don't. In addition, 1/6 of the students who don't speak
German do speak French. What fraction of the students speak German?
(1) Exactly 60 students speak French and German.
(2) Exactly 75 students speak neither French nor German.
Can you please fix the error

Legendary Member
Posts: 608
Joined: Sun Jun 19, 2011 11:16 am
Thanked: 37 times
Followed by:8 members

by saketk » Mon Oct 24, 2011 12:31 pm
LalaB wrote:Many of the students at the International School speak French or German or both. Among the students who
speak French, four times as many speak German as don't. In addition, 1/6 of the students who don't speak
German do speak French. What fraction of the students speak German?
(1) Exactly 60 students speak French and German.
(2) Exactly 75 students speak neither French nor German.
Things which are given to us.

Let X= People who speak only French i.e. they do not speak German
Y = People who speak only German i.e. they do not speak French
Z = People who speak both
N = People who do not speak any language. [remember the question says 'Many of the students'

Also, we know that Z = 4X
And, we also know that 1/6th People who do not speak German do speak French(this includes X and N)
This means X = 1/6 (X+N) or 5x = N or X = N/5

Statement 1 -- From this statement we can only find the number of student who speak both languages. Nothing can be deduced about the people who don't speak any of the two. Also, we cannot deduce anything about the student who speak only 1 language.

Insufficient

Statement 2-- From this statement we know N= 75
From this we can find X, which is 1/5 of N i.e. 15. We also know that Z = 4X or = 4*15 = 60
Again, we cannot deduce anything about people who speak ONLY GERMAN from this statement


Combine the two statement

we know the value of X, Z, N but still nothing about Y can be deduced.

IMO E

Senior | Next Rank: 100 Posts
Posts: 35
Joined: Wed Sep 18, 2013 11:12 pm
Thanked: 3 times

by SaraLotfy » Tue Oct 08, 2013 4:38 am
Can someone please provide OE and OA??

User avatar
Legendary Member
Posts: 1556
Joined: Tue Aug 14, 2012 11:18 pm
Thanked: 448 times
Followed by:34 members
GMAT Score:650

by theCodeToGMAT » Tue Oct 08, 2013 4:57 am
SaraLotfy wrote:Can someone please provide OE and OA??
According to me, the Answer is [spoiler]{E}[/spoiler]... What's your answer??

To find: G/Number of Students
Statement 1:
4A = 60 --> A = 15
NG = 6(A) = 90
We cannot find "G"; INSUFFICIENT

Statement 2:
NG - NG/6 = 75
NG = 75 * 6/5 = 90
We cannot find "G" ; INSUFFICIENT

Combining...
We cannot find "G"
INSUFFICIENT
Attachments
solution.JPG
R A H U L

Senior | Next Rank: 100 Posts
Posts: 35
Joined: Wed Sep 18, 2013 11:12 pm
Thanked: 3 times

by SaraLotfy » Tue Oct 08, 2013 5:47 am
Yes I got E using the double matrix method.

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Tue Oct 08, 2013 6:29 am
If anyone out there is wondering about the "double matrix method" that SaraLotfy mentioned (and theCodeToGMAT demonstrated), it's a technique can be used for most questions involving a population in which each member has two characteristics associated with it.
Here, we have a population of students, and the two characteristics are:
- speak German, or don't speak German
- speak French, or don't speak French

To learn more about this technique, watch our free video: https://www.gmatprepnow.com/module/gmat- ... ems?id=919

Then try these additional practice questions that can be solved using the Double Matrix Method:
- https://www.beatthegmat.com/mba/2011/05/ ... question-1
- https://www.beatthegmat.com/mba/2011/05/ ... question-2
- https://www.beatthegmat.com/mba/2011/05/ ... question-3
- https://www.beatthegmat.com/ds-quest-t187706.html
- https://www.beatthegmat.com/overlapping- ... 83320.html
- https://www.beatthegmat.com/finance-majo ... 67425.html
- https://www.beatthegmat.com/ds-french-ja ... 22297.html
- https://www.beatthegmat.com/sets-t269449.html#692540
- https://www.beatthegmat.com/in-costume-f ... tml#692116

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image