Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 05 Jul 2015, 21:22

### 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

# RAIN

Author Message
TAGS:
Manager
Joined: 20 May 2008
Posts: 57
Followers: 2

Kudos [?]: 6 [0], given: 1

RAIN [#permalink]  28 Jan 2009, 22:54
The probability that it will rain in NYC on any given day in July is 30%. what is the probability that it will rain on exactly 3 days from July 5 to July 10?

please give full explanation with reasons..
SVP
Joined: 17 Jun 2008
Posts: 1570
Followers: 12

Kudos [?]: 203 [0], given: 0

Re: RAIN [#permalink]  29 Jan 2009, 02:13
Total number of days between the two days (inclusive) = 6.

Probability of choosing 3 days on which it rains = 3/6 = 1/2
Probability that it rains on exactly these three days = (1/2)*30% = 15%
SVP
Joined: 29 Aug 2007
Posts: 2493
Followers: 59

Kudos [?]: 577 [0], given: 19

Re: RAIN [#permalink]  29 Jan 2009, 08:11
LoyalWater wrote:
The probability that it will rain in NYC on any given day in July is 30%. what is the probability that it will rain on exactly 3 days from July 5 to July 10?

please give full explanation with reasons..

= 6C3 (0.3)^3 (1-0.3)^(6-3)
= 20 (0.3^3)(0.7^3)
= 18.52%
_________________
SVP
Joined: 07 Nov 2007
Posts: 1824
Location: New York
Followers: 29

Kudos [?]: 564 [0], given: 5

Re: RAIN [#permalink]  29 Jan 2009, 08:23
agree with GMATTIGER approach.
_________________

Smiling wins more friends than frowning

Manager
Joined: 01 May 2008
Posts: 114
Location: São Paulo
Followers: 1

Kudos [?]: 5 [0], given: 0

Re: RAIN [#permalink]  08 Feb 2009, 15:43
GMATTIGER, can u explain why u multiplied 6C3?
Thanks a lot
Re: RAIN   [#permalink] 08 Feb 2009, 15:43
Similar topics Replies Last post
Similar
Topics:
Somebody has to go home if it rains on certian day and the 1 09 Aug 2006, 00:14
The probability that it will rain in NYC on any given day in 4 07 Aug 2006, 15:22
What's teh probability that it rains three consecutive days 7 05 Jul 2006, 14:05
Probabilty of rain 6 13 Feb 2006, 07:03
Display posts from previous: Sort by