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

 It is currently 18 Sep 2018, 12:31

### 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

# A person is to be selected at random from the group T of people...

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 12 Feb 2015
Posts: 427
A person is to be selected at random from the group T of people...  [#permalink]

### Show Tags

05 Jul 2018, 09:51
2
00:00

Difficulty:

45% (medium)

Question Stats:

53% (01:32) correct 47% (01:56) wrong based on 32 sessions

### HideShow timer Statistics

A person is to be selected at random from the group T of people. What is the probability that the person selected is a member of club E?
1. The probability that a person selected at random from group T is not a member of club D and is not a member of club E is $$\frac{1}{4}$$.
2. The probability that a person selected at random from group T is a member of club D and not a member of club E is $$\frac{5}{12}$$.

_________________

"Please hit +1 Kudos if you like this post"

_________________
Manish

"Only I can change my life. No one can do it for me"

Math Expert
Joined: 02 Aug 2009
Posts: 6785
Re: A person is to be selected at random from the group T of people...  [#permalink]

### Show Tags

05 Jul 2018, 10:40
CAMANISHPARMAR wrote:
A person is to be selected at random from the group T of people. What is the probability that the person selected is a member of club E?
1. The probability that a person selected at random from group T is not a member of club D and is not a member of club E is $$\frac{1}{4}$$.
2. The probability that a person selected at random from group T is a member of club D and not a member of club E is $$\frac{5}{12}$$.

Individually each statement cannot be sufficient as it talks of club D and club E both..

Combined..
Prob that person selected is neither from D nor from E is 1/4, so prob that the person is from one of D or E is 1-1/4=3/4
Statement II tells us D but not E is 5/12
Ans 3/4-5/12=4/12=1/3
Sufficient

If this were a PS problem...
Take total strength 12...
3/4 belong to D or E or Both so 12*3/4=9
But only D is 5/12, so 5 on only D
Remaining 9-5=4 in E
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

GMAT online Tutor

Director
Status: Learning stage
Joined: 01 Oct 2017
Posts: 835
WE: Supply Chain Management (Energy and Utilities)
Re: A person is to be selected at random from the group T of people...  [#permalink]

### Show Tags

05 Jul 2018, 11:29
CAMANISHPARMAR wrote:
A person is to be selected at random from the group T of people. What is the probability that the person selected is a member of club E?
1. The probability that a person selected at random from group T is not a member of club D and is not a member of club E is $$\frac{1}{4}$$.
2. The probability that a person selected at random from group T is a member of club D and not a member of club E is $$\frac{5}{12}$$.

Refer the affixed Venn diagram,
Question stem, probability that the person selected is a member of club E or a+c=?

statement-1:-
Given,he probability that a person selected at random from group T is not a member of club D and is not a member of club E is $$\frac{1}{4}$$
Or,$$n=\frac{1}{4}$$
we have, a+b+c+n=T
Or, ($$a+c)=T-n-b=1-\frac{1}{4}-b=\frac{3}{4}-b$$---------------(1) (T=1 because total probability is always 1)
Since 'b' is not provided, we can't determine a+c.
So, insufficient.
statement-2:-
Given, The probability that a person selected at random from group T is a member of club D and not a member of club E is $$\frac{5}{12}$$
Or, $$b=\frac{5}{12}$$--------------(2)
Since, we don't have info on "n", we can't determine a+c.
So, insufficient.

Now combining, from (1) & (2) we have $$a+c$$=$$\frac{3}{4}$$-$$\frac{5}{12}$$=$$\frac{1}{3}$$

Sufficient.

Ans. (C)
Hope it helps.
Attachments

Probab sum.JPG [ 14.3 KiB | Viewed 293 times ]

_________________

Regards,

PKN

Rise above the storm, you will find the sunshine

Re: A person is to be selected at random from the group T of people... &nbs [#permalink] 05 Jul 2018, 11:29
Display posts from previous: Sort by

# Events & Promotions

 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®.