Forum Home > GMAT > Quantitative > Problem Solving (PS)
Events & Promotions
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Aug 2211:00 AM EDT
-11:59 PM EDT
More and more TTP students are earning impressive scores on the GMAT. Now is the perfect time to join the many GMAT students who made the switch to TTP and surpassed their wildest expectations on test day.
Aug 2910:00 PM IST
-11:30 PM IST
With brand new features like:AI-driven Planner tool, 850+ data Insights practice questions and GMAT Focus Edition Adaptive mock tests with ESR+ analysis and personal mentor support, our course is the most comprehensive course for GMAT Focus Edition.
Aug 3112:00 PM EDT
-03:00 PM EDT
Save 20% on Target Test Prep and Score in the 100th Percentile in GMAT Verbal! Our course uses techniques such as topical study and spaced repetition to maximize knowledge retention and make studying simple and fun.
Aug 3103:00 PM EDT
-11:59 PM EDT
For a limited time use code FALL20 to save on prep. Valid on Complete Course, Advanced Course, Bootcamp Course, Tutoring, and the Executive Assessment Course. This discount ends September 16th.
Sep 0212:01 AM PDT
-11:59 PM PDT
On Monday the 2nd, GMAT Club Tests will be Absolutely Free! Including all the Quizzes, Questions, and Tests. 12 AM - 11:59 PM PST- Sep 07
11:00 AM IST
-01:00 PM IST
Attend this session to learn how to Deconstruct arguments, Pre-Think Author’s Assumptions, and apply Negation Test.
If a and b are integers, is a + b + 3 an odd integer?
[#permalink]
26 Jun 2017, 02:51
26 Jun 2017, 02:51
4
Kudos
49
Bookmarks
Expert Reply
Show timer
00:00
A
B
C
D
E
Difficulty:
15%
(low)
Question Stats:
80% (01:21) correct
20%
(01:22)
wrong
based on 3592
sessions
If a and b are integers, is a + b + 3 an odd integer?
(1) ab is an odd integer.
(2) a − b is an even integer.
(1) ab is an odd integer.
(2) a − b is an even integer.
Director
Joined: 04 Dec 2015
Posts: 620
Given Kudos: 276
Location: India
Concentration: Technology, Strategy
Schools: ISB '19 IIMB IIMA XLRI HEC Sept19 intake Rotman '21 NUS '21 NTU '20 Trinity MBA '20 Bocconi '21 Smurfit "21
WE:Information Technology (Consulting)
If a and b are integers, is a + b + 3 an odd integer?
[#permalink]
26 Jun 2017, 03:20
26 Jun 2017, 03:20
9
Kudos
5
Bookmarks
Bunuel wrote:
If a and b are integers, is a + b + 3 an odd integer?
(1) ab is an odd integer.
(2) a − b is an even integer.
(1) ab is an odd integer.
(2) a − b is an even integer.
(1) \(ab\) is an odd integer.
\(Odd * Odd = Odd\)
Therefore \(a\) and \(b\) should be Odd integers.
(\(Odd + Odd = Even\) ) and (\(Even + Odd = Odd\))
\(a + b = Even\)
\(a + b + 3 = Even + 3\) = Odd integer.
Hence I is Sufficient.
(2) \(a − b\) is an even integer.
\(Odd - Odd = Even\)
\(Even - Even = Even.\)
Therefore \(a\) and \(b\) could both either be Even or both be Odd.
If \(a\) and \(b\) are Odd. (\(Odd + Odd = Even\)) and (\(Even + Odd = Odd\))
\(a + b + 3 = Odd + Odd + 3 = Even + 3 = Odd\) --------- True.
If \(a\) and \(b\) are Even. (\(Even + Even = Even\)) and (\(Even + Odd = Odd\))
\(a + b + 3 = Even + Even + 3 = Even + 3 = Odd\) ------- True.
Hence II is Sufficient. Answer (D)...
Target Test Prep Representative
Joined: 14 Oct 2015
Status:Founder & CEO
Affiliations: Target Test Prep
Posts: 19389
Given Kudos: 286
Location: United States (CA)
Re: If a and b are integers, is a + b + 3 an odd integer?
[#permalink]
17 Nov 2017, 12:31
17 Nov 2017, 12:31
1
Kudos
4
Bookmarks
Expert Reply
Bunuel wrote:
If a and b are integers, is a + b + 3 an odd integer?
(1) ab is an odd integer.
(2) a − b is an even integer.
(1) ab is an odd integer.
(2) a − b is an even integer.
We need to determine whether a + b + 3 is odd, or in other words, whether a + b is even.
Statement One Alone:
ab is an odd integer.
Because ab is odd, we know that a and b must both be odd, and since odd + odd = even, a + b is even. Statement one alone is sufficient to answer the question.
Statement Two Alone:
a - b is an even integer.
Since a - b is even, a + b is also even. Statement two alone is sufficient.
Answer: D
