BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Consecutive Integer Question

Problem Solving — algebra and arithmetic (GMAT Focus Edition)
This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Senior | Next Rank: 100 Posts
Posts: 58
Joined: Sat Sep 25, 2010 10:07 am
Location: Belgrade, Serbia/ New York, USA
Thanked: 1 times

Consecutive Integer Question

by milanproda » Tue Dec 21, 2010 3:08 pm
Which of the following can be odd?

1- The sum of 7 consecutive numbers

2- The sum of 10 consecutive integers

3- The product of 13 consecutive integers

A- 2 ONLY
B- 1 AND 2 ONLY
C- 1 AND 3 ONLY
D- 2 AND 3 ONLY
E- 1, 2, AND 3

Would anyone happen to now the best way to solve this question without going through the long math?
Milan Prodanovic
[email protected]
Top
Source: — Quantitative Reasoning |
User avatar
Legendary Member
Posts: 1255
Joined: Fri Nov 07, 2008 2:08 pm
Location: St. Louis
Thanked: 312 times
Followed by:90 members

by Tani » Tue Dec 21, 2010 5:54 pm
1. Seven consecutive number can either be:
even + odd + even + odd + even + odd + even = which would be odd (try picking numbers - 2 thru 8)
or:
odd + even + odd + even + odd + even + odd = which would be even (try 1 thru 7)

2. sum of ten consecutive integers would be 5 even (total even) and 5 odd (total odd) whether starting with an odd or an even number. Therefore the grand total would be odd.

3. product of 13 consecutive integers must include either 6 or 7 multiples of two therefore it can only be even.

Therefore both 1 and 2 CAN BE odd.

no math needed!
Tani Wolff
Top
User avatar
Senior | Next Rank: 100 Posts
Posts: 58
Joined: Sat Sep 25, 2010 10:07 am
Location: Belgrade, Serbia/ New York, USA
Thanked: 1 times

by milanproda » Wed Dec 22, 2010 4:18 am
Tani, Thank you again! I have posted another consecutive integer problem on the forum, if you have a chance please help me out!
Milan Prodanovic
[email protected]
Top
Post new topic Post Reply
• Page 1 of 1