A doctor claims that 60% of the patients he examines are all : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 21 Jan 2017, 16:19

### 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

# A doctor claims that 60% of the patients he examines are all

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Intern
Joined: 01 Apr 2012
Posts: 2
Followers: 0

Kudos [?]: 5 [0], given: 1

A doctor claims that 60% of the patients he examines are all [#permalink]

### Show Tags

27 Dec 2012, 10:47
1
This post was
BOOKMARKED
00:00

Difficulty:

(N/A)

Question Stats:

100% (02:22) correct 0% (00:00) wrong based on 4 sessions

### HideShow timer Statistics

A doctor claims that 60% of the patients he examines are allergic to some type of weeds. What is the probability that exactly three of the next 4 patient he examines are allergic to weeds?

It'll be great if problem is solved step by step with explanation.
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7125
Location: Pune, India
Followers: 2137

Kudos [?]: 13681 [2] , given: 222

Re: A doctor claims that 60% of the patients he examines are all [#permalink]

### Show Tags

27 Dec 2012, 22:29
2
KUDOS
Expert's post
1
This post was
BOOKMARKED
mihir66 wrote:
A doctor claims that 60% of the patients he examines are allergic to some type of weeds. What is the probability that exactly three of the next 4 patient he examines are allergic to weeds?

It'll be great if problem is solved step by step with explanation.

The probability of a person being allergic = 6/10
Probability of a person not being allergic = 4/10

Probability of first person being allergic = 6/10
Probability of second person being allergic = 6/10
Probability of third person being allergic = 6/10
Probability of fourth person not being allergic = 4/10

Probability that exactly 3 of the next 4 people are allergic = (6/10)*(6/10)*(6/10)*(4/10)*4
We multiply by 4 because the non allergic person could be first, second or third. So we need to account for all sequences AAAN, AANA, ANAA, NAAA
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for \$199

Veritas Prep Reviews

Current Student
Joined: 06 Sep 2013
Posts: 2035
Concentration: Finance
GMAT 1: 770 Q0 V
Followers: 62

Kudos [?]: 594 [0], given: 355

Re: A doctor claims that 60% of the patients he examines are all [#permalink]

### Show Tags

12 May 2014, 06:45
I would guess this question is just (4)(3^3)(2) / (5^3)(5)=216/625

Therefore answer is A (J/K, would be nice to have some answer choices!)

Cheers!
J
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13489
Followers: 576

Kudos [?]: 163 [0], given: 0

Re: A doctor claims that 60% of the patients he examines are all [#permalink]

### Show Tags

06 Oct 2016, 15:10
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.
_________________
Re: A doctor claims that 60% of the patients he examines are all   [#permalink] 06 Oct 2016, 15:10
Similar topics Replies Last post
Similar
Topics:
2 Guy drives 60 miles to attend a meeting. Halfway through, he increases 4 08 Nov 2016, 23:03
5 The average score in an examination of 10 students of a class is 60 10 16 Sep 2016, 21:04
1 Joe drives 120 miles at 60 miles per hour, and then he drives the next 2 11 Oct 2015, 08:13
23 Kevin drove from A to B at a constant speed of 60 mph. Once he reache 17 13 Mar 2015, 06:38
2 In an examination 60% failed in Math and 40% failed in Frenc 10 01 Aug 2013, 10:35
Display posts from previous: Sort by

# A doctor claims that 60% of the patients he examines are all

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group and phpBB SEO 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®.