Register    Login    Search    Rss Feeds

Forums Home » Ask An Instructor » GMAT Math » Manhattan GMAT Math Strategy Guides


 Page 1 of 1 [ 4 posts ] 



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

If p, q and r are integers, is pq + r even? NP Ch2 Q16

Author Message
starburst83
 Post subject: If p, q and r are integers, is pq + r even? NP Ch2 Q16
 Post Posted: Wed Apr 08, 2009 8:12 pm 
Offline
Forum Guests


Posts: 2
Hi,

Apologies if this has been answered before, but if it has, I cannot find the answer in this forum.

To start, statement (2) states: "q + r is odd". The solution for statement (2) states that "The variables q and r must either both be odd or both be even..."

If "q + r is odd", then must not one be odd and the other even?

After all, O + E = O (and E + O = O).

However, if "q and r must either both be odd or both be even", then either case would result in an even: O + O = E and E + E = E

So how can we evaluate statement (2) if we state that they "must either both be odd or both be even"?

Secondly, shouldn't there be a comma after the first "q" in the question stem? Given that it is the second-to-last item in the list (right before "and"), which is greater than three items long, and that the GMAT prefers serial commas, and that this is a GMAT book? :)

And that is all for now.

Thanks for you time.

SB
Top 
esledge
 Post subject: Re: If p, q and r are integers, is pq + r even? NP Ch2 Q16
 Post Posted: Thu Apr 09, 2009 3:55 pm 
Offline
ManhattanGMAT Staff


Posts: 901
Location: St. Louis, MO
In the future, please post the full text of the question even if your question is only about part of it. For completeness, here it is :-)

If p, q, and r are integers, is pq + r even?

(1) p + r is even.
(2) q + r is odd.

starburst83 wrote:
To start, statement (2) states: "q + r is odd". The solution for statement (2) states that "The variables q and r must either both be odd or both be even..."

If "q + r is odd", then must not one be odd and the other even?

After all, O + E = O (and E + O = O).

However, if "q and r must either both be odd or both be even", then either case would result in an even: O + O = E and E + E = E

So how can we evaluate statement (2) if we state that they "must either both be odd or both be even"?

That is definitely an error. The chart for (2) is correct, as it lists every scenario such that EITHER q or r is even, but not both of them. Thanks for bringing this to our attention. We'll be sure to fix the text to match the chart before the next printing.

starburst83 wrote:
Secondly, shouldn't there be a comma after the first "q" in the question stem? Given that it is the second-to-last item in the list (right before "and"), which is greater than three items long, and that the GMAT prefers serial commas, and that this is a GMAT book? :)

Indeed :-) We'll get that comma in there, too.

_________________
Emily Sledge
Instructor
ManhattanGMAT
Top 
starburst83
 Post subject: Re: If p, q and r are integers, is pq + r even? NP Ch2 Q16
 Post Posted: Thu Apr 09, 2009 7:47 pm 
Offline
Forum Guests


Posts: 2
Thanks for the reply.

I'll be sure to include the complete question next time. :)
Top 
esledge
 Post subject: Re: If p, q and r are integers, is pq + r even? NP Ch2 Q16
 Post Posted: Mon Apr 20, 2009 1:18 pm 
Offline
ManhattanGMAT Staff


Posts: 901
Location: St. Louis, MO
No worries. Thanks again for the good catch.

_________________
Emily Sledge
Instructor
ManhattanGMAT
Top 
Display posts from previous:  Sort by  
 
 Page 1 of 1 [ 4 posts ] 





Who is online

Users browsing this forum: No registered users and 0 guests

 
 

 
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: