Last visit was: 18 Jul 2025, 15:32 It is currently 18 Jul 2025, 15:32
Home
GMAT
Messages
Tests
Schools
Events
Rewards
Chat
My Profile
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
Sub 505 Level|   Probability|      
User avatar
xmagedo
User avatar
Joined: 09 Jun 2010
Last visit: 13 Jan 2011
Posts: 41
Own Kudos:
174
 [3]
Given Kudos: 17
Posts: 41
Kudos: 174
 [3]
A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. 19 Jul 2010, 03:07
1
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

5% (low)

Question Stats:

96% (00:41) correct 4% (00:50) wrong based on 465 sessions

History

Date
Time
Result
Not Attempted Yet
A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. What is the probability that a block picked at random from the box will be red ?

A. 1/25
B. 1/12
C. 1/7
D. 1/5
E. 1/3
ShowHide Answer
Official Answer
B
avatar
ulm
avatar
Joined: 03 Jun 2010
Last visit: 20 Aug 2019
Posts: 95
Own Kudos:
599
Given Kudos: 40
Location: United States (MI)
Concentration: Marketing, General Management
Schools: Ross '15 (A) Darden '14 (D) Duke '15 (D)
WE:Business Development (Consumer Packaged Goods)
Products:
My Reviews
Schools: Ross '15 (A) Darden '14 (D) Duke '15 (D)
Posts: 95
Kudos: 599
A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. 19 Jul 2010, 03:40
Kudos
Add Kudos
Bookmarks
Bookmark this Post
There are 25 reds out of 300 blocks.

25/300 = 1/12 (B)
User avatar
ghettosquad
User avatar
Joined: 05 Jul 2010
Last visit: 23 Mar 2014
Posts: 8
Own Kudos:
23
Given Kudos: 7
Posts: 8
Kudos: 23
A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. 19 Jul 2010, 04:33
Kudos
Add Kudos
Bookmarks
Bookmark this Post
You're right. It would be B.
User avatar
EMPOWERgmatRichC
User avatar
Major Poster
Joined: 19 Dec 2014
Last visit: 31 Dec 2023
Posts: 21,788
Own Kudos:
12,502
Given Kudos: 450
Status:GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Expert
Expert reply
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Posts: 21,788
Kudos: 12,502
A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. 07 Dec 2017, 14:50
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi All,

This question is an example of a fairly straight-forward probability question.

Probability = (# of ways that give us what we "want")/(Total # of ways possible).

Here, we have a total of 25+100+175 = 300 blocks and 25 of those blocks are red. Thus, the probability of randomly pulling one red block from that group is...

25/300 = 1/12

Final Answer:
Show Spoiler
B


GMAT assassins aren't born, they're made,
Rich
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 18 Jul 2025
Posts: 21,145
Own Kudos:
26,202
 [1]
Given Kudos: 296
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 21,145
Kudos: 26,202
 [1]
A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. 05 Feb 2020, 05:53
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
xmagedo
A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. What is the probability that a block picked at random from the box will be red ?

A. 1/25
B. 1/12
C. 1/7
D. 1/5
E. 1/3

The box contains 25 + 100 + 175 = 300 blocks. Since there are 25 red blocks, the probability of picking one red block out of the box is 25/300 = 1/12.

Answer: B
User avatar
BrentGMATPrepNow
User avatar
Major Poster
Joined: 12 Sep 2015
Last visit: 13 May 2024
Posts: 6,755
Own Kudos:
34,126
Given Kudos: 799
Location: Canada
Expert
Expert reply
Posts: 6,755
Kudos: 34,126
A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. 01 Dec 2020, 07:58
Kudos
Add Kudos
Bookmarks
Bookmark this Post
xmagedo
A box contains 25 red blocks, 100 blue blocks, and 175 yellow blocks. What is the probability that a block picked at random from the box will be red ?

A. 1/25
B. 1/12
C. 1/7
D. 1/5
E. 1/3

There are 25 red blocks
There are 300 blocks in total (25 + 100 +175 = 300)

P(block is red) = (number of ways to select a red block)/(total number of outcomes)
= 25/300
= 1/12

Answer: B

Cheers,
Brent
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 37,454
Own Kudos:
1,013
Posts: 37,454
Kudos: 1,013
A box contains 25 red blacks, 100 blue blocks, and 175 yellow blocks. 19 Nov 2022, 09:04
Kudos
Add Kudos
Bookmarks
Bookmark this Post
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.
Moderators:
Bunuel
Math Expert
102619 posts
Krunaal
PS Forum Moderator
698 posts