GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 20 Oct 2018, 12:22

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Initially, how many black chips are in a box containing only red chips

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50007
Initially, how many black chips are in a box containing only red chips  [#permalink]

Show Tags

New post 24 Apr 2018, 06:04
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

76% (01:40) correct 24% (01:34) wrong based on 67 sessions

HideShow timer Statistics

Initially, how many black chips are in a box containing only red chips and black chips, all identical except for color?

(1) Initially, the ratio of red chips to black chips in the box is 3/25.
(2) If 12 red chips and 80 black chips are removed from the box, the probability of randomly drawing a red chip from the box is 1/11.

_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

examPAL Representative
User avatar
G
Joined: 07 Dec 2017
Posts: 721
Re: Initially, how many black chips are in a box containing only red chips  [#permalink]

Show Tags

New post 24 Apr 2018, 06:26
Bunuel wrote:
Initially, how many black chips are in a box containing only red chips and black chips, all identical except for color?

(1) Initially, the ratio of red chips to black chips in the box is 3/25.
(2) If 12 red chips and 80 black chips are removed from the box, the probability of randomly drawing a red chip from the box is 1/11.


We'll translate our data into equations to help us understand what we need to do.
This is a Precise approach..

(1) So r/b = 3/25. This is one equation with two variables and is insufficient.
Insufficient.

(2) We can write this as an equation to help us out:
(r - 12) / (r + b - 92) = 1/11
This is an equation with two variables and has infinite solutions.
Insufficient.

Combined:
We now have two equations with two variables we can solve. (But we won't bother!)
Sufficient

(C) is our answer.
_________________

Image
Sign up for 7-day free trial
Image

I am a CR Expert - Ask Me ANYTHING about CR
I am a DS Expert - Ask Me ANYTHING about DS


Watch free GMAT tutorials in Math, Verbal, IR, and AWA.

GMAT test takers: Watch now the GMAC interview with the people who write the GMAT test!
We discussed the chances of improving a GMAT score; how important the first questions on the test are; what to do if you don’t have enough time to complete a whole section; and more.

You can watch all the action from the interview here.

Director
Director
avatar
P
Joined: 02 Oct 2017
Posts: 650
Re: Initially, how many black chips are in a box containing only red chips  [#permalink]

Show Tags

New post 11 May 2018, 23:43
I) ratio is given so
R/B=3X/25X

On different values of x, different values appear so insufficient

II)R-12/B-80=1/11
Don't know relation between R and B so insufficient

Combining both
Putting value of I) in statement II)
We can get unique value for both R and B
Sufficient

Give kudos if it helps

Posted from my mobile device
_________________

Give kudos if you like the post

GMAT Club Bot
Re: Initially, how many black chips are in a box containing only red chips &nbs [#permalink] 11 May 2018, 23:43
Display posts from previous: Sort by

Initially, how many black chips are in a box containing only red chips

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.