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

 It is currently 03 Jul 2015, 12:29

### 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

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 certain office supply store stocks two sizes

Author Message
TAGS:
Intern
Joined: 28 Jul 2008
Posts: 30
Followers: 0

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

A certain office supply store stocks two sizes [#permalink]  03 Dec 2008, 02:51
1
This post was
BOOKMARKED
Please kindly assist to clarify the solution of this problem. Thank you very much....
Attachments

GMAT Prep Math.doc [62 KiB]

SVP
Joined: 30 Apr 2008
Posts: 1889
Location: Oklahoma City
Schools: Hard Knocks
Followers: 35

Kudos [?]: 473 [0], given: 32

Re: GMAT Prep: Combination [#permalink]  03 Dec 2008, 05:22
A certain office supply store stocks 2 sizes of self-stick notepads, each in 4 colors: blue, green, yellow, or pink. The store packs the notepads in packages that contain either 3 notepads of the same size and the same color or 3 notepads of the same size and of 3 different colors. If the order in which the colors are packed is not considered, how many different packages of the types described above are possible?

(a) 6
(b) 8
(c) 16
(d) 24
(e) 32
_________________

------------------------------------
J Allen Morris
**I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a$$. GMAT Club Premium Membership - big benefits and savings SVP Joined: 30 Apr 2008 Posts: 1889 Location: Oklahoma City Schools: Hard Knocks Followers: 35 Kudos [?]: 473 [0], given: 32 Re: GMAT Prep: Combination [#permalink] 03 Dec 2008, 05:33 The answer is (c) 16. First we need to determine the number of ways we can pull 3 different colors from 4. This would be combinatorics (spelling?) $$C_3^4 = \frac{4!}{3!1!} = 4$$ 4! = 24 3! = 6 and 1! = 1. so 24 / 6 = 4. (This could also be seen as selecting 1 from 4, with that 1 being the color NOT in the package, because when you select 1, you leave 3 in a group as well. Same cat, different way to skin it.) Now we have to take into account the different sizes (2 sizes) and the ways to package (all same color or different colors.) If pacakged all with the same color, then there are 4 ways to package the notepads because there are 4 colors. So for each method of colors, either different or the same, there are 2 sizes, so 4 x 2 = 8. Now for the ones that are packaged with different colors, there are 4 combinations and 2 sizes, so 4 x 2 = 8. 8 + 8 = 16. Now that you see the basis for this, look at it this way. Number of ways to package based upon color * number of sizes = Total combinations. Ways to package 3 different colors = 4 and 4 ways if all same color, so a total of 8 possibilities. 2 sizes = 8 x 2 = 16. jallenmorris wrote: A certain office supply store stocks 2 sizes of self-stick notepads, each in 4 colors: blue, green, yellow, or pink. The store packs the notepads in packages that contain either 3 notepads of the same size and the same color or 3 notepads of the same size and of 3 different colors. If the order in which the colors are packed is not considered, how many different packages of the types described above are possible? (a) 6 (b) 8 (c) 16 (d) 24 (e) 32 _________________ ------------------------------------ J Allen Morris **I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a$$.

GMAT Club Premium Membership - big benefits and savings

Intern
Joined: 28 Jul 2008
Posts: 30
Followers: 0

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

Re: GMAT Prep: Combination [#permalink]  03 Dec 2008, 08:33
Thanks a lot ...
Re: GMAT Prep: Combination   [#permalink] 03 Dec 2008, 08:33
Similar topics Replies Last post
Similar
Topics:
A certain office supply store stocks 2 sizes of self-stick 2 31 Dec 2008, 08:40
A certain office supply store stocks 2 sizes of self stick 4 13 Oct 2008, 18:19
A certain office supply store stocks 2 sizes of self-stick 2 02 May 2008, 22:50
A certain office supply store stocks 2 sizes of self-stick 3 04 Apr 2006, 01:43
A certain office supply store stocks 2 sizes of self-stick 16 23 Oct 2005, 17:09
Display posts from previous: Sort by