A 3-character alpha-numeric code does have the following properties - the first character can be any number except 0 and 9, the second character can be any small letter between a to z, excluded, and the third character can have any of those characters possible for the first two places. How many such codes can be formed?
A. 26
B. 64
C. 520
D. 6144
E. 9360
OA D
Source: e-GMAT
A 3-character alpha-numeric code does have the following
This topic has expert replies
-
- Moderator
- Posts: 7187
- Joined: Thu Sep 07, 2017 4:43 pm
- Followed by:23 members
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
- GMATGuruNY
- GMAT Instructor
- Posts: 15539
- Joined: Tue May 25, 2010 12:04 pm
- Location: New York, NY
- Thanked: 13060 times
- Followed by:1906 members
- GMAT Score:790
Number of options for the first character = 8. (Of the 10 digits, any digit but 0 or 9.)BTGmoderatorDC wrote:A 3-character alpha-numeric code does have the following properties - the first character can be any digit except 0 and 9, the second character can be any small letter between a and z, excluding a and z, and the third character can be any of those characters possible for the first two places. How many such codes can be formed?
A. 26
B. 64
C. 520
D. 6144
E. 9360
Number of options for the second character = 24. (Of the 26 letters in the alphabet, any but a or z.)
Number of options for the third character = (number of options for the first character) + (number of options for the second character) = 8+24 = 32.
To combine these options, we multiply:
8*24*32 = large integer with a units digit of 4.
The correct answer is D.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
GMAT/MBA Expert
- Scott@TargetTestPrep
- GMAT Instructor
- Posts: 7247
- Joined: Sat Apr 25, 2015 10:56 am
- Location: Los Angeles, CA
- Thanked: 43 times
- Followed by:29 members
There are 8 choices for the first digit, 26 - 2 = 24 choices for the second digit, and 24 + 8 = 32 choices for the last digit. The number of ways to create the code is:BTGmoderatorDC wrote:A 3-character alpha-numeric code does have the following properties - the first character can be any number except 0 and 9, the second character can be any small letter between a to z, excluded, and the third character can have any of those characters possible for the first two places. How many such codes can be formed?
A. 26
B. 64
C. 520
D. 6144
E. 9360
OA D
Source: e-GMAT
8 x 24 x 32 = 6,144
Answer: D
Scott Woodbury-Stewart
Founder and CEO
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews