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

Redeem

number system

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 468
Joined: Mon Jul 25, 2011 10:20 pm
Thanked: 29 times
Followed by:4 members

number system

by vipulgoyal » Mon Jul 08, 2013 2:40 am
Number x is obtained by inserting two "+"s into the ordered numbers 1, 2, 3, 4, and 5, for example, 1+23+45=69. Is x odd?
(1) x>100
(2) x<300
Top
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 358
Joined: Thu Apr 18, 2013 9:46 am
Location: Jeddah, Saudi Arabia
Thanked: 42 times
Followed by:7 members
GMAT Score:730

by faraz_jeddah » Mon Jul 08, 2013 3:45 am
Statement 1:

x > 100

x = 1 + 2 + 345 = 348 (EVEN)
x = 1 + 234 + 5 = 240 (EVEN)
x = 123 + 4 + 5 = 132 (EVEN)

No matter where you place the + signs, x will always be even and NOT ODD ==> Sufficient


Statement 2:

x < 300

1 + 23 + 45 = 69 (ODD)
1 + 234 + 5 = 240 (EVEN)

Multiple answers and cannot say with certainty ==> Not Sufficient


OA should be A

Hope that helps.
Top
Master | Next Rank: 500 Posts
Posts: 468
Joined: Mon Jul 25, 2011 10:20 pm
Thanked: 29 times
Followed by:4 members

by vipulgoyal » Mon Jul 08, 2013 4:14 am
what about 312 + 4 + 5 = 321
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Mon Jul 08, 2013 7:28 am
vipulgoyal wrote:what about 312 + 4 + 5 = 321
Good idea, but the question says that the numbers (1, 2, 3, 4, 5) are ordered. So, they must stay in that order. Your example does not preserve the order.

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Post new topic Post Reply
• Page 1 of 1