Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 26 Apr 2015, 13:20

### 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

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# A three-digit code for certain logs uses the digits 0, 1, 2,

 Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
VP
Joined: 03 Apr 2007
Posts: 1376
Followers: 3

Kudos [?]: 260 [0], given: 10

A three-digit code for certain logs uses the digits 0, 1, 2, [#permalink]  01 Jun 2008, 08:15
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
A three-digit code for certain logs uses the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 according to the
following constraints. The first digit cannot be 0 or 1, the second digit must be 0 or 1, and the
second and third digits cannot both be 0 in the same code. How many different codes are
possible?
A. 144
B. 152
C. 160
D. 168
E. 176
Director
Joined: 10 Sep 2007
Posts: 949
Followers: 7

Kudos [?]: 205 [0], given: 0

Re: PS-Code [#permalink]  01 Jun 2008, 08:34
One set
First digit can be selected from 8 numbers (leaving 0 and 1).
Second digit can be selected from 1 numbers (0).
Third digit can be selected from 9 numbers (leaving 0).
Total Number = 8*1*9 = 72

Second set
First digit can be selected from 8 numbers (leaving 0 and 1).
Second digit can be selected from 1 numbers (1).
Third digit can be selected from 10 numbers (no restriction).
Total Number = 8*1*10 = 80

Net total = 72 + 80 = 152

Answer B.
SVP
Joined: 28 Dec 2005
Posts: 1583
Followers: 2

Kudos [?]: 86 [0], given: 2

Re: PS-Code [#permalink]  01 Jun 2008, 09:57
i said A ... i think i interpreted the question properly. I read the last restriction as meaning that the last two numbers cant be the same, i.e. they both cannot be 0 nor can they both be 1.

So i broke it down into two cases: one with the second digit is 0 , and other case when second digit is 1.

8x1x9 (9 in the last place because you cant repeat what was in the second spot). Thats 72 choices ... and then another 72 for the second case for a total of 144
Director
Joined: 10 Sep 2007
Posts: 949
Followers: 7

Kudos [?]: 205 [0], given: 0

Re: PS-Code [#permalink]  01 Jun 2008, 10:08
pmenon wrote:
i said A ... i think i interpreted the question properly. I read the last restriction as meaning that the last two numbers cant be the same, i.e. they both cannot be 0 nor can they both be 1.

So i broke it down into two cases: one with the second digit is 0 , and other case when second digit is 1.

8x1x9 (9 in the last place because you cant repeat what was in the second spot). Thats 72 choices ... and then another 72 for the second case for a total of 144

Question says "both be 0 in the same code" but does not say same about 1 so you cannot assume that 1 at both places is not allowed.
SVP
Joined: 28 Dec 2005
Posts: 1583
Followers: 2

Kudos [?]: 86 [0], given: 2

Re: PS-Code [#permalink]  01 Jun 2008, 10:12
Doh !!!

Yes, youre right ... just re-read the question again. No mention about 1s not being able to repeat. See ,this is what is going to kill me.
Re: PS-Code   [#permalink] 01 Jun 2008, 10:12
Similar topics Replies Last post
Similar
Topics:
A three-digit code for certain logs uses the digits 0, 1, 2, 3 14 Nov 2008, 20:52
A three-digit code for certain logs uses the digits 0, 1, 2, 1 14 Nov 2008, 15:57
A threee-digit code for certain logs use the digits 1 05 Oct 2008, 01:17
1 A three digit code for certain logs uses the digits 0, 3 05 Jul 2008, 11:45
A three-digit code for certain logs uses the digits 0, 1, 2, 2 28 Apr 2008, 12:26
Display posts from previous: Sort by

# A three-digit code for certain logs uses the digits 0, 1, 2,

 Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.