It is currently 22 Nov 2017, 19:13

### 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 jar contains only b black marbles, w white marbles

Author Message
Manager
Joined: 15 Nov 2006
Posts: 216

Kudos [?]: 81 [0], given: 0

Location: Ohio
A certain jar contains only b black marbles, w white marbles [#permalink]

### Show Tags

04 Apr 2007, 16:47
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

A certain jar contains only b black marbles, w white marbles and r red marbles. If a marble is picked at random from the jar, is the probability that the marble chosen be red greater than the probability that the marble chosen will be white?
(1) r/(b+w)>w/(b+r)
(2) b-w>r

Kudos [?]: 81 [0], given: 0

Director
Joined: 14 Jan 2007
Posts: 775

Kudos [?]: 179 [0], given: 0

### Show Tags

06 Apr 2007, 03:29
Probability of choosing red marble = r/(b+w+r)
Probability of choosing white marble = w/(b+w+r)

To compare these two probabilities, we should know the relation between r and w
Lets consider the statement 1:
r/(b+w) > w/(b+r)
r(b+r) > (b+w)w
rb+r^2 -bw_w^2 > 0
b(r-w) + r^2 -w^2 > 0
b(r-w) + (r+w)(r-w) > 0
(r-w)(b+r+w) > 0
as we know b+r+w will always be positive
so r-w> 0
r > w
hence we can say the prob of choosing red marble is greater. SUFF

Statement2 : does not establish any relation between r and w. INSUFF

Kudos [?]: 179 [0], given: 0

Director
Joined: 31 Mar 2007
Posts: 574

Kudos [?]: 81 [0], given: 0

### Show Tags

08 Apr 2007, 04:30
I got A as well.

However, this seems like a difficult question for the GMAT; would something like this appear?

Kudos [?]: 81 [0], given: 0

VP
Joined: 28 Mar 2006
Posts: 1367

Kudos [?]: 38 [0], given: 0

### Show Tags

08 Apr 2007, 06:00
I got A as well.

However, this seems like a difficult question for the GMAT; would something like this appear?

YOu never know

Kudos [?]: 38 [0], given: 0

Manager
Joined: 25 Aug 2007
Posts: 70

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

Schools: HBS '10

### Show Tags

13 Oct 2007, 15:23
I had this question in GMATprep ... So you think about it

I got A as well.

However, this seems like a difficult question for the GMAT; would something like this appear?

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

Director
Joined: 30 Nov 2006
Posts: 591

Kudos [?]: 318 [0], given: 0

Location: Kuwait

### Show Tags

13 Oct 2007, 16:15
You Rock vshaunak !!

This question is from GMATPrep 2 ; So it is definately a GMAT level question. I have seen much more difficult problems on the REAL GMAT test.

Kudos [?]: 318 [0], given: 0

Director
Joined: 22 Aug 2007
Posts: 566

Kudos [?]: 73 [0], given: 0

### Show Tags

14 Oct 2007, 00:11
A,

r/(b+w+r) compare to w/(b+w+r)

since denominators are same, we need to compare only r and w

1) r/(b+w)> w/(b+r), since r,b, and w all are positive we can cross multiply.
r(b+r) > w(b+w)
b is same for both sides, thus r > w always. SUFF.

2) b-w>r, fastest is to try few numbers

w=3, r=2, b=5 -----------> r<w
w=2, r=3, b=5------------> r>w, thus INSUFF.

Kudos [?]: 73 [0], given: 0

Re: DS Question Marbles   [#permalink] 14 Oct 2007, 00:11
Display posts from previous: Sort by