It is currently 19 Oct 2017, 09:43

### 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

# There is a 90% chance that a registered voter in Burghtown

Author Message
Director
Joined: 15 Aug 2005
Posts: 794

Kudos [?]: 75 [0], given: 0

Location: Singapore
There is a 90% chance that a registered voter in Burghtown [#permalink]

### Show Tags

18 Sep 2005, 01:00
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

There is a 90% chance that a registered voter in Burghtown voted in the last election. IF five registered voters are chosen at random, what is the approximate likelihood that excatly four of them voted in the last election?

A. 26.2%
B. 32.8%
C. 43.7%
D. 59.0%
E. 65.6%

_________________

Cheers, Rahul.

Kudos [?]: 75 [0], given: 0

Manager
Joined: 14 Jul 2005
Posts: 104

Kudos [?]: 9 [0], given: 0

Location: Sofia, Bulgaria

### Show Tags

18 Sep 2005, 01:37

Once you identify that this is binomial distribution case, you should simply use the formula.

P = (0.9^4) * (0.1^1) * C(5,4) = 32.8%

Narrative: I assume you just multiplied 0.9 four times to reach the answer. That's not enough, because this way you can't be sure about the voting status of the 5th person. So you plug in his 10% probability, and you get (0.9^4) * (0.1^1) ~ 0.066. But this is incomplete, because we haven't considered if the 10% person shows up 1st, 2nd, etc. In order to stir things up, we multiply by C(5,4) = C(5,1) to account for all possible positions of the non-voter among the voters.

Kudos [?]: 9 [0], given: 0

Intern
Joined: 30 Aug 2005
Posts: 9

Kudos [?]: 11 [0], given: 0

### Show Tags

18 Sep 2005, 12:09
Yes, agreed with vasild. Using Binomial distribution is the quickest way to solve this problem.

Kudos [?]: 11 [0], given: 0

Intern
Joined: 19 Aug 2005
Posts: 41

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

### Show Tags

18 Sep 2005, 21:24
got B too using binomial distribition also

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

18 Sep 2005, 21:24
Display posts from previous: Sort by

# There is a 90% chance that a registered voter in Burghtown

 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®.