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

 It is currently 25 May 2017, 10:43

### 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 box contains 7 Yellow balls and 5 blue balls. Select 3

Author Message
Senior Manager
Joined: 25 Dec 2003
Posts: 359
Location: India
Followers: 1

Kudos [?]: 37 [0], given: 0

A box contains 7 Yellow balls and 5 blue balls. Select 3 [#permalink]

### Show Tags

12 Jul 2004, 07:48
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

A box contains 7 Yellow balls and 5 blue balls. Select 3 balls randomly. What is the probability of choosing 3 blue ones.

_________________

Giving another SHOT

Senior Manager
Joined: 05 Feb 2004
Posts: 290
Location: USA
Followers: 1

Kudos [?]: 5 [0], given: 0

### Show Tags

12 Jul 2004, 08:45
3 balls can be chosen from 12 in : 12C3 ways
3 blue balls can be chosen from 5 blues in: 5C3 ways

Hence required prob: 5C3/12C3 = 10/220 = 1/22!!
Director
Joined: 05 Jul 2004
Posts: 898
Followers: 4

Kudos [?]: 52 [0], given: 0

### Show Tags

12 Jul 2004, 08:46
Probability = (Fav. outcome) / (Total Outcome)

Total : selecting 3 balls from 12 balls = 12C3
Favourable : selecting 3 blue from 5 blue balls = 5C3

P = 5C3 / 12C3 (Very lengthy calculation)
Joined: 31 Dec 1969
Location: Russian Federation
GMAT 3: 740 Q40 V50
GMAT 4: 700 Q48 V38
GMAT 5: 710 Q45 V41
GMAT 6: 680 Q47 V36
GMAT 9: 740 Q49 V42
GMAT 11: 500 Q47 V33
GMAT 14: 760 Q49 V44
WE: Supply Chain Management (Energy and Utilities)
Followers: 0

Kudos [?]: 233 [0], given: 104556

### Show Tags

12 Jul 2004, 11:45
I would do:

5/12 x 4/11 x 3/10 = 1/22 and forget about the combinations formula.
12 Jul 2004, 11:45
Display posts from previous: Sort by