There is a set of beads, each of which is painted either red : GMAT Data Sufficiency (DS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 20 Jan 2017, 07:15

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

There is a set of beads, each of which is painted either red

Author Message
TAGS:

Hide Tags

Intern
Joined: 26 Aug 2013
Posts: 11
Followers: 0

Kudos [?]: 3 [0], given: 19

There is a set of beads, each of which is painted either red [#permalink]

Show Tags

30 Aug 2013, 01:06
3
This post was
BOOKMARKED
00:00

Difficulty:

85% (hard)

Question Stats:

49% (02:53) correct 51% (01:36) wrong based on 167 sessions

HideShow timer Statistics

There is a set of beads, each of which is painted either red or blue. The beads are split, with each bead being cut in half. Then they are merged, where all the halves are randomly reassembled back into the same number of beads that there were to begin with. This results in r red beads, b blue beads, and p beads that are half red and half blue. Before the split and merge, were there more red beads than blue beads?

(1) after the split and merge, the probability of picking a bead that is only red is less than the probability of picking a bead that is at least half blue.
(2) After the split and merge, the probability of picking a bead that is only blue is greater than the probability of picking a bead that is at least half red.

[Reveal] Spoiler:
Well, I got the answer but it took me so long to solve it.
Can someone help me to solve this kind of questions quicker?
[Reveal] Spoiler: OA
Intern
Joined: 31 Jan 2013
Posts: 17
Schools: ISB '15
WE: Consulting (Energy and Utilities)
Followers: 0

Kudos [?]: 45 [1] , given: 18

Re: probability question from Princeton review [#permalink]

Show Tags

30 Aug 2013, 02:12
1
KUDOS
Consider the Number of Red and Blue beads as R and B respectively and, after splitting, the number of beads as R1,B1 and P(mixed)

We need to prove R>B
From the given information, We could say
R+B = R1+B1+P
Or
R = R1+P/2
B = B1+P/2

1) Given R1<B1+P -
R1<B+P/2 or R1+P/2<B+P
R<B+P - from this equation, there is no way we can interpret about R or B. Hence not Sufficient

2) Given B1>R1+P -
From this we could definitely say B>B1>R1+P
B> (R1+P/2)+P/2
So we can definitely say,
B>R
hence St2 is sufficent to answer the question.

I hope this helps
/SW
Current Student
Joined: 06 Sep 2013
Posts: 2035
Concentration: Finance
GMAT 1: 770 Q0 V
Followers: 62

Kudos [?]: 594 [0], given: 355

Re: There is a set of beads, each of which is painted either red [#permalink]

Show Tags

02 Jun 2014, 07:53
I don't get it. Bunuel could you solve alternatively?

Question is to express half/half red and blue balls algebraically

Thanks!
Cheers
J
Current Student
Joined: 06 Sep 2013
Posts: 2035
Concentration: Finance
GMAT 1: 770 Q0 V
Followers: 62

Kudos [?]: 594 [0], given: 355

Re: There is a set of beads, each of which is painted either red [#permalink]

Show Tags

02 Jun 2014, 07:53
I don't get it. Bunuel could you solve alternatively?

Question is to express half/half red and blue balls algebraically

Thanks!
Cheers
J
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13461
Followers: 575

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

Re: There is a set of beads, each of which is painted either red [#permalink]

Show Tags

02 Mar 2016, 04:17
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.
_________________
Re: There is a set of beads, each of which is painted either red   [#permalink] 02 Mar 2016, 04:17
Similar topics Replies Last post
Similar
Topics:
The king set a big party. Each guest had to wear either a red tunic or 2 21 Nov 2016, 01:26
2 There are a number of red beads and white beads in a jar. If Mike were 1 07 Apr 2016, 07:36
3 A cube is painted with blue and red color such that each color is pain 3 02 Sep 2014, 01:06
3 Each of the balls in a jar is either red, green or blue. If 3 30 Nov 2012, 19:21
1 A box contains 30 beads, of which 15 are blue, 9 are red 2 19 Mar 2012, 12:24
Display posts from previous: Sort by