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

Redeem

Experts Please Help on this DS!

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 11
Joined: Fri Jun 24, 2011 8:52 am
Followed by:1 members

Experts Please Help on this DS!

by srini1988 » Tue Jul 26, 2011 9:44 pm
A brick road has orange,blue and purple bricks along its path.In a single row of orange,blue and purple bricks, every purple brick is preceded immediately by an orange brick and every orange brick is preceded immediately by a blue brick. What color is the 26th brick in the row.

1.The 24th brick in the row is not orange

2.The 25th brick in the row is not blue
Top
Source: — Data Sufficiency |
Senior | Next Rank: 100 Posts
Posts: 93
Joined: Sun Jul 17, 2011 10:30 am
Thanked: 1 times
Followed by:2 members

by ColumbiaVC » Wed Jul 27, 2011 3:16 pm
E
Top
User avatar
GMAT Instructor
Posts: 1031
Joined: Thu Jul 03, 2008 1:23 pm
Location: Malibu, CA
Thanked: 716 times
Followed by:255 members
GMAT Score:750

by Brian@VeritasPrep » Wed Jul 27, 2011 3:46 pm
Neat question - thanks for posting this one!

Here I think it's a matter of making the options concrete. We know that the order of bricks is:

Blue, Orange, Purple, Blue, Orange Purple

Statement 1 tells us that #24 is NOT Orange, so we know we have two options:

24 25 26* 27
B O P* B.....

or

P B O* P......

So we don't know - 26 could be purple or orange.

Statement 2 similarly limits us to two options, starting with #25 as Not Blue, so either Orange or Purple. The sequence is then:

25 26^ 27
O P* B
or
P B* O

Again, this isn't sufficient as #26 could be either purple or blue.

But taken together, we have:

St. 1: #26 is either Purple or Orange
St. 2: #26 is either Purple or Blue

The only color consistent with both statements is Purple, so we know that the 26th brick must be Purple, and therefore the statement is sufficient.
Brian Galvin
GMAT Instructor
Chief Academic Officer
Veritas Prep

Looking for GMAT practice questions? Try out the Veritas Prep Question Bank. Learn More.
Top
Post new topic Post Reply
• Page 1 of 1