NEW HERE? LEARN MORE
closeclose
Last visit was: 28 Apr 2024, 12:25 It is currently 28 Apr 2024, 12:25
Decision Tracker
My Rewards
New posts
New comers' posts

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

If 55 percent of a group of people have brown hair and 80 percent of

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92977
Own Kudos [?]: 619695 [7]
Given Kudos: 81613
Send PM
CAT Tests Forum Quiz Mode
If 55 percent of a group of people have brown hair and 80 percent of [#permalink] New post   07 Feb 2019, 01:18
6
Bookmarks
Expert Reply
00:00
A
B
C
D
E

Difficulty:

35% (medium)

Question Stats:

73% (02:10) correct 27% (02:34) wrong based on 177 sessions
Hide Show timer Statistics
If 55 percent of a group of people have brown hair and 80 percent of the same group do not have red hair, what fraction of those who do not have brown hair have red hair?


A. 1/4

B. 4/11

C. 4/9

D. 5/9

E. 4/5
ShowHide Answer
Official Answer
C
Most Helpful Reply
User avatar
L
KarishmaB
Tutor
Joined: 16 Oct 2010
Posts: 14836
Own Kudos [?]: 64976 [6]
Given Kudos: 428
Location: Pune, India
Send PM
Re: If 55 percent of a group of people have brown hair and 80 percent of [#permalink] New post   07 Feb 2019, 03:27
1
Kudos
5
Bookmarks
Expert Reply
Bunuel wrote:
If 55 percent of a group of people have brown hair and 80 percent of the same group do not have red hair, what fraction of those who do not have brown hair have red hair?


A. 1/4

B. 4/11

C. 4/9

D. 5/9

E. 4/5


55% have brown hair. So 45% do not have brown hair.
80% do not have red hair. So 20% have red hair.

"what fraction of those who do not have brown hair have red hair?"

Those who have red hair as a fraction of those who do not have brown hair = 20/45 = 4/9

Answer (C)
General Discussion
User avatar
L
Archit3110
GMAT Club Legend
GMAT Club Legend
Joined: 18 Aug 2017
Status:You learn more from failure than from success.
Posts: 8022
Own Kudos [?]: 4100 [0]
Given Kudos: 242
Location: India
Concentration: Sustainability, Marketing
GMAT Focus 1:
545 Q79 V79 DI73
GPA: 4
WE:Marketing (Energy and Utilities)
Send PM
GMAT ToolKit User
Re: If 55 percent of a group of people have brown hair and 80 percent of [#permalink] New post   07 Feb 2019, 01:27
Bunuel wrote:
If 55 percent of a group of people have brown hair and 80 percent of the same group do not have red hair, what fraction of those who do not have brown hair have red hair?


A. 1/4

B. 4/11

C. 4/9

D. 5/9

E. 4/5


can be solved using 2x2 matrix
IMO C
4/9
User avatar
S
NinetyFour
Manager
Manager
Joined: 22 Sep 2018
Posts: 191
Own Kudos [?]: 173 [0]
Given Kudos: 78
Send PM
Re: If 55 percent of a group of people have brown hair and 80 percent of [#permalink] New post   07 Feb 2019, 14:49
Bunuel wrote:
If 55 percent of a group of people have brown hair and 80 percent of the same group do not have red hair, what fraction of those who do not have brown hair have red hair?


A. 1/4

B. 4/11

C. 4/9

D. 5/9

E. 4/5


If 55% have brown hair, that means 45% do NOT have brown hair.

We know that 80% do not have red hair, so 20% do have red hair.

They are apart of the same group so 45% * x = 20%

x = 4/9 (answer choice C)
User avatar
L
ScottTargetTestPrep
Target Test Prep Representative
Joined: 14 Oct 2015
Status:Founder & CEO
Affiliations: Target Test Prep
Posts: 18769
Own Kudos [?]: 22073 [0]
Given Kudos: 283
Location: United States (CA)
Send PM
Re: If 55 percent of a group of people have brown hair and 80 percent of [#permalink] New post   10 Feb 2019, 08:44
Expert Reply
Bunuel wrote:
If 55 percent of a group of people have brown hair and 80 percent of the same group do not have red hair, what fraction of those who do not have brown hair have red hair?


A. 1/4

B. 4/11

C. 4/9

D. 5/9

E. 4/5


If 55% of the group have brown hair, then 100% - 55% = 45% of the group do not have brown hair (which includes people who have red hair). And since 80% of the group do not have red hair, then 20% of the group do have red hair. Thus, the ratio, or fraction, of those that do have red hair to those who do not have brown hair is:

0.20/0.45 = 20/45 = 4/9

Answer: C
User avatar
G
KanishkM
Director
Director
Joined: 09 Mar 2018
Posts: 783
Own Kudos [?]: 453 [0]
Given Kudos: 123
Location: India
Schools: DeGroote'21 Desautels '21 NUS '21
Send PM
Re: If 55 percent of a group of people have brown hair and 80 percent of [#permalink] New post   10 Feb 2019, 08:54
Bunuel wrote:
If 55 percent of a group of people have brown hair and 80 percent of the same group do not have red hair, what fraction of those who do not have brown hair have red hair?


A. 1/4

B. 4/11

C. 4/9

D. 5/9

E. 4/5


One of its kind :-o, Let total be 100 people

------------BH------No BH------
RH-------------------------------20
No RH---------------------------80
-----------55---------45--------100

those who do not have brown hair have red hair
20/45

4/9

C
User avatar
bumpbot
Non-Human User
Joined: 09 Sep 2013
Posts: 32725
Own Kudos [?]: 822 [0]
Given Kudos: 0
Send PM
Re: If 55 percent of a group of people have brown hair and 80 percent of [#permalink] New post   09 Jul 2023, 06:44
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.
GMAT Club Bot
gmatclubot
Re: If 55 percent of a group of people have brown hair and 80 percent of [#permalink]
09 Jul 2023, 06:44
Moderators:
Bunuel
Math Expert
92977 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions