Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 29 May 2017, 07:51

### 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

# How many ways can 5 identical black balls and 7 identical

Author Message
Director
Joined: 29 Oct 2004
Posts: 854
Followers: 5

Kudos [?]: 212 [0], given: 0

How many ways can 5 identical black balls and 7 identical [#permalink]

### Show Tags

27 Dec 2004, 14:12
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

How many ways can 5 identical black balls and 7 identical whie balls be arranged in a row so that no 2 black balls are together?
(A) 56
(B) 64
(C) 65
(D) 316
(E) 560
Intern
Joined: 26 Dec 2004
Posts: 6
Followers: 0

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

### Show Tags

27 Dec 2004, 14:34
A : 56
The black balls have to be placed between the 7 white balls.. If we arranage the 7 white balls as _W_W_W_W_W_W_W_. We have 8 spots for balck balls and we have to put 5 of them. therefore required result = 8C5 = 56.
Director
Joined: 29 Oct 2004
Posts: 854
Followers: 5

Kudos [?]: 212 [0], given: 0

### Show Tags

27 Dec 2004, 14:50
Yep (A)
Nice approach.
27 Dec 2004, 14:50
Display posts from previous: Sort by