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

It is currently 23 Oct 2018, 20:00

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

The first basket contains 4 blue and 5 red marbles; the second basket

  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: 50058
The first basket contains 4 blue and 5 red marbles; the second basket  [#permalink]

Show Tags

New post 28 Jan 2018, 21:26
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

65% (01:43) correct 35% (01:53) wrong based on 36 sessions

HideShow timer Statistics

The first basket contains 4 blue and 5 red marbles; the second basket contains 3 blue and 4 red marbles. One marble is randomly extracted from the first basket and put into the second. After that, a marble is extracted from the second basket. What is the probability that this marble is blue?

A. 1/3
B. 15/36
C. 31/72
D. 4/9
E. 11/18

_________________

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

Senior Manager
Senior Manager
User avatar
G
Joined: 17 Oct 2016
Posts: 322
Location: India
Concentration: Operations, Strategy
GPA: 3.73
WE: Design (Real Estate)
GMAT ToolKit User Premium Member
Re: The first basket contains 4 blue and 5 red marbles; the second basket  [#permalink]

Show Tags

New post 28 Jan 2018, 21:53
1
Has to be C.

There are two cases.

Case 1:
Selection of blue from first bag followed by the selection of blue from the second bag.

Selection of blue from first bag = 4/9.
Now the total blue balls in second bag becomes 4 with total balls as 8.
Hence selection of blue from second bag = 4/8.
Total probability = 4/9*4/8 =16/72

Case 2:
Selection of red from first bag followed by the selection of blue from the second bag.

Selection of red from first bag = 5/9.
Now the total red balls in second bag becomes 5 with total balls as 8.
Hence selection of blue from second bag = 3/8.
Total probability = 5/9*3/8 =15/72

Total probability = 16/72 + 15/72 = 31/72
_________________

Help with kudos if u found the post useful. Thanks

Intern
Intern
avatar
B
Joined: 03 Jun 2015
Posts: 21
WE: Information Technology (Computer Software)
Re: The first basket contains 4 blue and 5 red marbles; the second basket  [#permalink]

Show Tags

New post 28 Jan 2018, 23:23
Bunuel wrote:
The first basket contains 4 blue and 5 red marbles; the second basket contains 3 blue and 4 red marbles. One marble is randomly extracted from the first basket and put into the second. After that, a marble is extracted from the second basket. What is the probability that this marble is blue?

A. 1/3
B. 15/36
C. 31/72
D. 4/9
E. 11/18


We have 2 events and based on their sequences, following combinations are possible :
1. Take blue from basket 1 and place it in basket 2. In this case, probability of picking blue is :
4/9 * 4/8 =16/72
2. Take red from basket 1 and place it in basket 2. In this case, probability of picking blue is :
5/9*3/8=15/72

Since either of two events are possible, we have
16/72 + 15/72 = 31/72 as answer.
So answer should be C.
_________________

A dream doesn't become reality through magic; it takes sweat, determination and hard work.

GMAT Club Bot
Re: The first basket contains 4 blue and 5 red marbles; the second basket &nbs [#permalink] 28 Jan 2018, 23:23
Display posts from previous: Sort by

The first basket contains 4 blue and 5 red marbles; the second basket

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


cron
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®.