Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 23 May 2017, 15:14

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Each of the 30 students in a class is either male or female

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 24 Mar 2010
Posts: 347
Followers: 7

Kudos [?]: 111 [0], given: 4

Each of the 30 students in a class is either male or female [#permalink]

### Show Tags

30 Sep 2012, 00:03
1
This post was
BOOKMARKED
00:00

Difficulty:

55% (hard)

Question Stats:

64% (02:55) correct 36% (01:45) wrong based on 149 sessions

### HideShow timer Statistics

Each of the 30 students in a class is either male or female, and has blonde, brown, or red hair. If one student is to be randomly selected from the class, what is the probability that the student will either be female or have brown hair?

(1) The probability that the student will be both female and have brown hair is 0.1
(2) The probability that the student will be female minus the probability that the student will have brown hair is 0.25
[Reveal] Spoiler: OA

Last edited by Bunuel on 30 Sep 2012, 04:48, edited 1 time in total.
Renamed the topic and edited the question.
Director
Joined: 22 Mar 2011
Posts: 612
WE: Science (Education)
Followers: 101

Kudos [?]: 947 [0], given: 43

Re: Each of the 30 students in a class [#permalink]

### Show Tags

30 Sep 2012, 04:35
Shawshank wrote:
Each of the 30 students in a class is either male or female, and has blonde, brown, or red hair. If one student is to be randomly selected from the class, what is the probability that the student will either be female or have brown hair?

1. The probability that the student will be both female and have brown hair is 0.1
2. The probability that the student will be female minus the probability that the student will have brown hair is 0.25

Two remarks:
a) Since the question is about a probability, we can consider 100 students or any other number, 30 is not important.
b) We can ignore that those who don't have brown hair can have either blonde or red hair.

We can work with Venn diagrams or the 2 X 2 table. And for either one, we can consider probabilities or actual number of people. For those who prefer visualizing.
Looking at the complementary probability, we see that in order to answer the question, it is enough to know the probability for MALE and NOT BROWN HAIR.
Or, if we know one of them, we must know the other one as well.

(1) Not sufficient.
We don't know how many male students with brown hair.

(2) Again not sufficient.
We don't know anything about the male students with brown hair.

(1) and (2) together: From the above, we can see that there is no information about the male students, and definitely there might be some of them with brown hair.
Not sufficient.

_________________

PhD in Applied Mathematics
Love GMAT Quant questions and running.

Current Student
Joined: 06 Sep 2013
Posts: 2005
Concentration: Finance
Followers: 68

Kudos [?]: 643 [2] , given: 355

Re: Each of the 30 students in a class is either male or female [#permalink]

### Show Tags

21 Jan 2014, 14:56
2
KUDOS
Shawshank wrote:
Each of the 30 students in a class is either male or female, and has blonde, brown, or red hair. If one student is to be randomly selected from the class, what is the probability that the student will either be female or have brown hair?

(1) The probability that the student will be both female and have brown hair is 0.1
(2) The probability that the student will be female minus the probability that the student will have brown hair is 0.25

I suggest one just apply logic instead of Venn Diagram/Double set matrix

So what do we have here,
OK ...

We want P(F) + P(B) - (PuB) (We know they are not mutually exclusive as per the question stem

So we have

Statement 1

PuB = 0.1

Statement 2

P(F) - (P(B)) = 0.25

We don't have enough info

Statements (1) and (2)

We need P(F) + P(B) - (PuB)
We have PuB = 0.1 and P(F) - (P(B)) = 0.25
Can I make it happen? Don't think so

E
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15406
Followers: 648

Kudos [?]: 205 [0], given: 0

Re: Each of the 30 students in a class is either male or female [#permalink]

### Show Tags

20 Oct 2015, 01:35
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.
_________________
Senior Manager
Joined: 20 Aug 2015
Posts: 397
Location: India
GMAT 1: 760 Q50 V44
Followers: 29

Kudos [?]: 260 [0], given: 10

Re: Each of the 30 students in a class is either male or female [#permalink]

### Show Tags

21 Oct 2015, 03:17
Shawshank wrote:
Each of the 30 students in a class is either male or female, and has blonde, brown, or red hair. If one student is to be randomly selected from the class, what is the probability that the student will either be female or have brown hair?

(1) The probability that the student will be both female and have brown hair is 0.1
(2) The probability that the student will be female minus the probability that the student will have brown hair is 0.25

Given: Each of the 30 students in a class is either male or female, and has blonde, brown, or red hair
Required: what is the probability that the randomly student will either be female or have brown hair
Let P(F) = Probability of Female
P(B) = Probability of Blonde hair

We need P(F) + P(B) - P(F) n P(B)

Statement 1:
P(F) n P(B) = 0.1 (i)
We do not know anything about P(F) + P(B)

INSUFFICIENT

Statement 2:
P(F) - P(B) = 0.25 (ii)
We cannot find P(F) + P(B) - P(F) n P(B)

INSUFFICIENT

Statement 1 and Statement 2 Combined :
Using (i) and (ii) also, we cannot find P(F) + P(B) - P(F) n P(B)

INSUFFICIENT
Option E
_________________

Reach out to us at bondwithus@gmatify.com

Re: Each of the 30 students in a class is either male or female   [#permalink] 21 Oct 2015, 03:17
Similar topics Replies Last post
Similar
Topics:
14 Each of the 50 students participating in a workshop is either an under 4 15 Nov 2016, 04:25
1 All of the shoppers in a grocery store are either male or female. 3 04 Jan 2017, 13:36
3 There are 42 students in a group. If each student is either 17 26 Jan 2016, 22:42
7 Each of the 30 students in a class is either male or female, 6 29 Jun 2013, 03:51
11 Of the students in a certain class, 55% of the female and 13 27 Sep 2016, 07:31
Display posts from previous: Sort by