Register    Login    Search    Rss Feeds

Forums Home » Ask An Instructor » GMAT Math » GMAT Prep Math


 Page 1 of 1 [ 3 posts ] 



  Print view Print view Previous topic Previous topic | Next topic Next topic
 

A wooden rod is cut

Author Message
candace_washington1980
 Post subject: A wooden rod is cut
 Post Posted: Thu Aug 06, 2009 6:40 am 
Offline
Forum Guests


Posts: 17
Gmat prep data sufficiency question

A wooden rod is cut into two pieces. What is the length of the longer piece?

1. One of the pieces is 20 inches longer than the other piece.
2. The length of the shorter piece is 1/3 the length of the longer piece

I thought both statements were not sufficient but the answer is both statements together are sufficient, but neither statement alone is sufficient. How?
Top 
furtadovinod
 Post subject: Re: A wooden rod is cut
 Post Posted: Thu Aug 06, 2009 11:11 am 
Offline
Students


Posts: 28
candace_washington1980 wrote:
Gmat prep data sufficiency question

A wooden rod is cut into two pieces. What is the length of the longer piece?

1. One of the pieces is 20 inches longer than the other piece.
2. The length of the shorter piece is 1/3 the length of the longer piece

I thought both statements were not sufficient but the answer is both statements together are sufficient, but neither statement alone is sufficient. How?


The best way to solve such questions is to put everything into equations. The question stem does not give us anything, but let us assume that
s - length of the shorter piece.
l - length of the longer piece.

Statement 1: l = s + 20
1 equation. 2 unknowns. Therefore statement 1 is insufficient by itself.

Statement 2: s = l/3. 3s = l.
1 equation. 2 unknowns. Therefore statement 2 is insufficient by itself.

Together: We can substitute the value of l from statement 2 into statement 1.
3s = s + 20
2s = 20
s = 10
Therefore, l = 30. And hence the answer is C - Both statements together are sufficient.
Top 
candace_washington1980
 Post subject: Re: A wooden rod is cut
 Post Posted: Thu Aug 06, 2009 12:26 pm 
Offline
Forum Guests


Posts: 17
Oh ok thanks!
Top 
Display posts from previous:  Sort by  
 
 Page 1 of 1 [ 3 posts ] 





Who is online

Users browsing this forum: No registered users and 1 guest

 
 

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to: