Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 49320

Bag 1 contains 10 blue, 8 gold, and 6 red chips, all identical except
[#permalink]
Show Tags
29 Mar 2018, 23:40
Question Stats:
80% (02:36) correct 20% (01:30) wrong based on 82 sessions
HideShow timer Statistics
Bag 1 contains 10 blue, 8 gold, and 6 red chips, all identical except for color. Bag 2 contains 8 blue, 2 gold, and 2 red chips, also all identical except for color. Two chips, one from each bag, are randomly drawn, one after the other. What is the probability that neither chip will be gold? (A) 5/18 (B) 4/9 (C) 1/2 (D) 5/9 (E) 2/3
Official Answer and Stats are available only to registered users. Register/ Login.
_________________
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? Extrahard Quant Tests with Brilliant Analytics



Manager
Joined: 05 Feb 2016
Posts: 145
Location: India
Concentration: General Management, Marketing
WE: Information Technology (Computer Software)

Re: Bag 1 contains 10 blue, 8 gold, and 6 red chips, all identical except
[#permalink]
Show Tags
29 Mar 2018, 23:59
Since we have to all 10 blue balls are identical to number of ways of fetching them =1 similarly for gold=1 and red=1 Since three different colours are there so picking one ball will be 3C1 from two different bag total numbers=3C1*3C1 except gold=2C1*2C1 probability=4/9



BSchool Forum Moderator
Joined: 07 Jan 2016
Posts: 748
Location: India

Re: Bag 1 contains 10 blue, 8 gold, and 6 red chips, all identical except
[#permalink]
Show Tags
30 Mar 2018, 00:16
Bunuel wrote: Bag 1 contains 10 blue, 8 gold, and 6 red chips, all identical except for color. Bag 2 contains 8 blue, 2 gold, and 2 red chips, also all identical except for color. Two chips, one from each bag, are randomly drawn, one after the other. What is the probability that neither chip will be gold?
(A) 5/18 (B) 4/9 (C) 1/2 (D) 5/9 (E) 2/3 10+8+6 = 24 no gold = 16/24 8+2+2=12 no gold = 10/12 no gold = 16/24 x 10/12 = 2/3x5/6 = 5/9



DS Forum Moderator
Joined: 27 Oct 2017
Posts: 729
Location: India
Concentration: International Business, General Management
GPA: 3.64
WE: Business Development (Energy and Utilities)

Re: Bag 1 contains 10 blue, 8 gold, and 6 red chips, all identical except
[#permalink]
Show Tags
30 Mar 2018, 00:57
Dear kunal You have ignored the importance of the number of balls in the probability. Please see the approach. The total number of balks in first bag =24. Number of balls other than gold =16. Probability if selecting a ball other than gold =16/24= 2/3 Similarly for second bag, total balls =12, balls other than gold = 10. Hence probability of selecting balls other than gold = 10/12 =5/6. Required probability = 2/3 *5/6 =5/9 kunalcvrce wrote: Since we have to all 10 blue balls are identical to number of ways of fetching them =1 similarly for gold=1 and red=1 Since three different colours are there so picking one ball will be 3C1 from two different bag total numbers=3C1*3C1 except gold=2C1*2C1 probability=4/9
_________________
Win GMAT CLUB Tests  Weekly Quant Quiz Contest SC: Confusable words All you need for Quant, GMAT PS Question Directory,GMAT DS Question Directory Error log/Key Concepts Combination Concept: Division into groups Question of the Day (QOTD) Free GMAT CATS



Manager
Joined: 05 Feb 2016
Posts: 145
Location: India
Concentration: General Management, Marketing
WE: Information Technology (Computer Software)

Re: Bag 1 contains 10 blue, 8 gold, and 6 red chips, all identical except
[#permalink]
Show Tags
30 Mar 2018, 01:15
Hi gmatbuster,
Since all same colour balls are identical total number dosent matter.... because even you pick any ball the ball will be same only so total number of ways will be 1. 24C1 will come into picture when we can differentiate the ball. So that there will 24+1(if ball is not picked)ways to pick a ball



Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 3528
Location: United States (CA)

Re: Bag 1 contains 10 blue, 8 gold, and 6 red chips, all identical except
[#permalink]
Show Tags
04 Apr 2018, 17:49
Bunuel wrote: Bag 1 contains 10 blue, 8 gold, and 6 red chips, all identical except for color. Bag 2 contains 8 blue, 2 gold, and 2 red chips, also all identical except for color. Two chips, one from each bag, are randomly drawn, one after the other. What is the probability that neither chip will be gold?
(A) 5/18 (B) 4/9 (C) 1/2 (D) 5/9 (E) 2/3 The probability that the chip from bag 1 is not a gold chip is 16/24 = 2/3. The probability that the chip from bag 2 is not a gold chip is 10/12 = 5/6. Since we want both events to occur (i.e., bag 1 not gold and bag 2 not gold), we multiply the two respective probabilities. Thus, the probability that neither chip will be gold is 2/3 x 5/6 = 10/18 = 5/9. Answer: D
_________________
Scott WoodburyStewart
Founder and CEO
GMAT Quant SelfStudy Course
500+ lessons 3000+ practice problems 800+ HD solutions



Intern
Joined: 06 Dec 2017
Posts: 7

Bag 1 contains 10 blue, 8 gold, and 6 red chips, all identical except
[#permalink]
Show Tags
18 Apr 2018, 01:36
I am going through this problem and wonder why can't I solve this problem as per below and still get the answer 5/9? 1  (8/24x 2/12) probability that the chip from bag A is gold x probability that the chip from bag B is gold Answer i get is 1  1/18 = 17/18




Bag 1 contains 10 blue, 8 gold, and 6 red chips, all identical except &nbs
[#permalink]
18 Apr 2018, 01:36






