OG 12 DS Q 65

Expert replies

jainrahul1985: Master | Next Rank: 500 Posts; Posts: 228; Joined: Sun Aug 17, 2008 8:08 am; Thanked: 4 times

by jainrahul1985 » Wed Apr 21, 2010 8:27 pm

Q 65 ) How many integers are there between but not including integers r and s ?
(1) s -r = 10
(2) there are 9 integers between , but not including , r+1 ans s+1

Like this post

Source: Beat The GMAT — Data Sufficiency | Wed Apr 21, 2010 8:27 pm

ansumania: Master | Next Rank: 500 Posts; Posts: 301; Joined: Sun Mar 21, 2010 3:18 pm; Thanked: 4 times

by ansumania » Wed Apr 21, 2010 9:50 pm

IMO D

Like this post

tpr-becky: GMAT Instructor; Posts: 509; Joined: Wed Apr 21, 2010 1:08 pmFollowed by: 85 members; Location: Irvine, CA; Thanked: 199 times; GMAT Score:750

by tpr-becky » Wed Apr 21, 2010 9:51 pm

the number of integers between r and s not including either one is s-r-1 This is because s-r will give you the number of numbers between including one end point.

1 - statement 1 gives you s-r so it is sufficient

statement 2 also tells you that there are 9 integers between r+1 and s+1 - this is the same as the number of integers between r and s because you added one to each number.

Therefore the answer is D.

Becky
Master GMAT Instructor
The Princeton Review
Irvine, CA

Like this post

eaakbari: Master | Next Rank: 500 Posts; Posts: 435; Joined: Mon Mar 15, 2010 6:15 amFollowed by: 1 member; Thanked: 32 times

by eaakbari » Thu Apr 22, 2010 1:37 am

Since it is a DS question , you can jump straight to D, as all the info you need is provided

Whether you think you can or can't, you're right.
- Henry Ford

Like this post

Lasve: Senior | Next Rank: 100 Posts; Posts: 30; Joined: Tue Dec 20, 2011 2:11 pmFollowed by: 1 member; Thanked: 4 times

by Lasve » Thu Jan 12, 2012 3:50 am

I, too, have a problem with this question:
Since is not said that r & s has to be positive, what if the former was <0?

That would mean that would mean that one of the numbers between r & s is 0, that is not an integer. so For example if
s=9
r=-1

s-r= 10
BUT the number of integers would be 8 (1,2,3,4,5,6,7,8)

s=9 & r=-1 Would also comply with the second statement.

Like this post

vinaypat: Newbie | Next Rank: 10 Posts; Posts: 5; Joined: Thu Feb 09, 2012 4:00 am; Thanked: 1 times

by vinaypat » Tue Mar 27, 2012 3:07 pm

0 is a integer

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

560 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review