GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 19 Jun 2018, 11:24

### 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

# From the set of numbers x, y, t, z and w, how many different

Author Message
TAGS:

### Hide Tags

Intern
Joined: 05 Jun 2010
Posts: 3
From the set of numbers x, y, t, z and w, how many different [#permalink]

### Show Tags

19 Jun 2010, 15:48
2
3
00:00

Difficulty:

55% (hard)

Question Stats:

56% (01:12) correct 44% (01:31) wrong based on 98 sessions

### HideShow timer Statistics

From the set of numbers x, y, t, z and w, how many different combinations can we have without the t in them? Ex:. (x,y), (x), (w,z,y,x), etc and (x,y)=(y,x)

A. 10
B. 14
C. 15
D. 16
E. 30
Math Expert
Joined: 02 Sep 2009
Posts: 46167

### Show Tags

19 Jun 2010, 15:59
2
Gusano97 wrote:
Could anybody help me with these problem?

From the set of numbers x, y, t, z and w, how many different combinations can we have without the t in them? Ex:. (x,y), (x), (w,z,y,x), etc and (x,y)=(y,x)

A)10
B)14
C)15
D)16
E)30

There are 4 letter without t: x, y, z, and w, so:
$$C^1_4+C^2_4+C^3_4+C^4_4=4+6+4+1=15$$

_________________
CEO
Joined: 17 Nov 2007
Posts: 3486
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40

### Show Tags

22 Jun 2010, 15:23
2
1
Another way: Any letter (x, y, z, w) can be included or not. So, we have 2^4 combinations - 1 empty combination = 15 combinations
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Manager
Joined: 22 May 2015
Posts: 106
Re: From the set of numbers x, y, t, z and w, how many different [#permalink]

### Show Tags

10 Apr 2017, 17:09
Question is to find no of combinations of x,y,z,w

Choosing only 1 letter - 4C1 ways = 4
Choosing only 2 letter - 4C2 ways = 6
Choosing only 3 letter - 4C3 ways = 4
Choosing only 4 letter - 4C4 ways = 1

Total possible combinations = 4+6+4+1 = 15
_________________

Consistency is the Key

Re: From the set of numbers x, y, t, z and w, how many different   [#permalink] 10 Apr 2017, 17:09
Display posts from previous: Sort by