A certain basket contains 10 apples, 7 of which are red and : Quant Question Archive [LOCKED]
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 24 Jan 2017, 10:09

### 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 certain basket contains 10 apples, 7 of which are red and

Author Message
Senior Manager
Joined: 23 May 2005
Posts: 266
Location: Sing/ HK
Followers: 1

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

A certain basket contains 10 apples, 7 of which are red and [#permalink]

### Show Tags

20 Oct 2006, 01:11
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

A certain basket contains 10 apples, 7 of which are red and 3 of which are green. If 3 different apples are to be selected at random from the basket, what is the probability that 2 of the apples selected will be red and 1 will be green?

a. 7/40
b. 7/20
c. 49/100
d. 21/40
e. 7/10

OA is D. Can someone explain how you arrive at D? Thx
Director
Joined: 05 Feb 2006
Posts: 898
Followers: 3

Kudos [?]: 107 [0], given: 0

### Show Tags

20 Oct 2006, 04:03
My method is to look at all the possibilities one by one:

Probability: RRG=(7/10)*(6/9)*(3/8)=7/40
Probability: GRR=(3/10)*(7/9)*(6/8)=7/40
Probability: RGR=(7/10)*(3/9)*(6/8)=7/40

(7/40)+(7/40)+(7/40)=21/40

D
Manager
Joined: 07 Jun 2006
Posts: 111
Followers: 2

Kudos [?]: 26 [0], given: 0

### Show Tags

20 Oct 2006, 09:37
(7C2 * 3C1)/(10C3) = 63/120 = 21/40..........D
CEO
Joined: 20 Nov 2005
Posts: 2911
Schools: Completed at SAID BUSINESS SCHOOL, OXFORD - Class of 2008
Followers: 24

Kudos [?]: 273 [0], given: 0

### Show Tags

20 Oct 2006, 09:45
Total cases = 10C3
Cases when 2 are red and one is green = 7C2 * 3C1

Prob = 7C2 * 3C1/ 10C3
= 21/40
_________________

SAID BUSINESS SCHOOL, OXFORD - MBA CLASS OF 2008

Senior Manager
Joined: 30 Aug 2006
Posts: 374
Followers: 3

Kudos [?]: 65 [0], given: 0

### Show Tags

20 Oct 2006, 09:50
as above,

3 scenarios:

RRG,RGR,GRR

RRG=(7/10*6/9*3/8) = 7/40

others are same probability, so 7*3/40 = 21/40
Manager
Joined: 04 Oct 2006
Posts: 122
Location: Florida, Argentina, UK
Followers: 2

Kudos [?]: 2 [0], given: 0

### Show Tags

20 Oct 2006, 19:30
londonluddite wrote:
as above,

3 scenarios:

RRG,RGR,GRR

RRG=(7/10*6/9*3/8) = 7/40

others are same probability, so 7*3/40 = 21/40

Perfectly explained!
)   [#permalink] 20 Oct 2006, 19:30
Display posts from previous: Sort by