The probability of pulling a black ball out of a glass jar : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 20 Jan 2017, 13:22

### 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

# The probability of pulling a black ball out of a glass jar

Author Message
TAGS:

### Hide Tags

Manager
Joined: 07 Feb 2010
Posts: 159
Followers: 2

Kudos [?]: 552 [0], given: 101

The probability of pulling a black ball out of a glass jar [#permalink]

### Show Tags

17 Dec 2010, 04:39
1
This post was
BOOKMARKED
00:00

Difficulty:

15% (low)

Question Stats:

74% (01:42) correct 26% (00:48) wrong based on 74 sessions

### HideShow timer Statistics

The probability of pulling a black ball out of a glass jar is 1/X. The probability of pulling a black ball out of a glass jar and breaking the jar is 1/Y. What is the probability of breaking the jar?

A. 1/(XY)
B. X/Y
C. Y/X
D. 1/(X+Y)
E. 1/(X-Y)
[Reveal] Spoiler: OA
Math Expert
Joined: 02 Sep 2009
Posts: 36583
Followers: 7087

Kudos [?]: 93280 [4] , given: 10555

The probability of pulling a black ball out of a glass jar [#permalink]

### Show Tags

17 Dec 2010, 04:48
4
KUDOS
Expert's post
1
This post was
BOOKMARKED
anilnandyala wrote:
The probability of pulling a black ball out of a glass jar is 1/X. The probability of pulling a black ball out of a glass jar and breaking the jar is 1/Y. What is the probability of breaking the jar?

a) 1/(XY).
b) X/Y.
c) Y/X.
d) 1/(X+Y).
e) 1/(X-Y).

Probability of A and B:
When two events are independent, the probability of both occurring is the product of the probabilities of the individual events: $$P(A \ and \ B) = P(A)*P(B)$$

P(break & black) = P(break) * P(black) --> 1/y=P(break)*1/x --> P(break)=x/y.

_________________
Intern
Status: Power perceived is power achieved
Joined: 06 Dec 2010
Posts: 5
Location: United States
GMAT 1: 610 Q46 V28
GMAT 2: Q V
Followers: 0

Kudos [?]: 5 [0], given: 10

Re: The probability of pulling a black ball out of a glass jar [#permalink]

### Show Tags

17 Dec 2010, 23:38
pretty new to this forum and have a question. do you not use plug in or substitution and try to use just the math specifically?

If substitute here, much easier, i think. 1/x substitute x=5 1/y = substitute y = 6 (it has to be less likely to break and black ball, otherwise, there wouldnt be a black ball in the jar) then you have...

1/5 * P(both) = 1/6

5(1/5 * P(both)) = (1/6)5

P(both) = 5/6
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13465
Followers: 575

Kudos [?]: 163 [0], given: 0

Re: The probability of pulling a black ball out of a glass jar [#permalink]

### Show Tags

25 May 2016, 07:05
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Director
Joined: 18 Oct 2014
Posts: 924
Location: United States
GMAT 1: 660 Q49 V31
GPA: 3.98
Followers: 93

Kudos [?]: 234 [0], given: 69

Re: The probability of pulling a black ball out of a glass jar [#permalink]

### Show Tags

25 May 2016, 07:24
anilnandyala wrote:
The probability of pulling a black ball out of a glass jar is 1/X. The probability of pulling a black ball out of a glass jar and breaking the jar is 1/Y. What is the probability of breaking the jar?

A. 1/(XY)
B. X/Y
C. Y/X
D. 1/(X+Y)
E. 1/(X-Y)

P of pulling a black ball out of a glass jar AND breaking the jar = 1/Y
P of pulling a black ball out of a glass jar is 1/X
Lets say P of breaking the jar = n

That means 1/X*n=1/Y
n= X/Y

_________________

I welcome critical analysis of my post!! That will help me reach 700+

Re: The probability of pulling a black ball out of a glass jar   [#permalink] 25 May 2016, 07:24
Similar topics Replies Last post
Similar
Topics:
There are 18 balls in a jar. You take out 3 blue balls without putting 2 11 Jul 2016, 11:42
The probability of pulling a black ball out of a glass jar is 1/X. The 3 10 Jul 2016, 07:44
4 A jar contains 4 black and 3 white balls. If you pick two ba 6 30 Aug 2013, 05:09
4 The weight of a glass of jar is 20% of the weight of the jar 6 25 Nov 2012, 02:42
2 A jar contains only x black balls and y white balls 3 06 Jun 2009, 03:54
Display posts from previous: Sort by