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
 

Is the three-digit number

Author Message
Bhaskar
 Post subject: Is the three-digit number
 Post Posted: Tue Jun 24, 2008 11:46 pm 
Is the three-digit number less than 550?

(1) The product of the digits in n is 30
(2) The sum of the digits in n is 10

I think the answer should be A, but GMATprep says that the answer should be C. Why?

My reasoning:
(1) 2x5x3=30
532<550 so yes we can answer the three digit number is less than 550.

(2) not sufficient because 2+4+4=10 and 442<550 but 7+2+1=10 and 721>550

I don't understand why it is C.
Top 
guest
 Post subject:
 Post Posted: Wed Jun 25, 2008 7:37 am 
You are forgetting 1,6,5 combination...even i forgot it and then someone explained it to me. :) With 1,6,5 and 2,3,5 we can't answer with A and hence would need both as second one eliminates1,6,5 combination
Top 
RonPurewal
 Post subject:
 Post Posted: Thu Jun 26, 2008 4:12 am 
Offline
ManhattanGMAT Staff


Posts: 6765
guest wrote:
You are forgetting 1,6,5 combination...even i forgot it and then someone explained it to me. :) With 1,6,5 and 2,3,5 we can't answer with A and hence would need both as second one eliminates1,6,5 combination

you got it.

don't forget 1 as a possible component of a product! if you're thinking solely in terms of primes, then it's easy to forget about 1 (because 1 isn't prime).

if you ever get a problem like this again, though, you'll be sure not to forget 1, though, because you'll be reminded of this problem. that's the power of making mistakes - you'll learn the relevant lessons much better than you would if you hadn't made the mistakes.
Top 
Display posts from previous:  Sort by  
 
 Page 1 of 1 [ 3 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: