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 Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 350,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

A shipment of 8 TV sets contains 2 black and white sets and [#permalink]
03 Oct 2007, 22:44

2

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

35% (medium)

Question Stats:

68% (02:23) correct
32% (01:33) wrong based on 250 sessions

A shipment of 8 TV sets contains 2 black and white sets and 6 color sets. If 2 TV sets are to be chosen at random from this shipment, what is the probability that at least 1 of the 2 sets chosen will be a black and white set?

A shipment of 8 TV sets contains 2 black and white sets and [#permalink]
24 Jan 2012, 06:23

Expert's post

beckee529 wrote:

not sure if this question has been brought up. i think there is a typo in the answer choices but just wanted to make sure:

A shipment of 8 TV sets contains 2 black and white sets and 6 color sets. If 2 TV sets are to be chosen at random from this shipment, what is the probability that at least 1 of the 2 sets chosen will be a black and white set?

A) 1/7 B) 1/4 C) 5/14 D) 11/28 E) 13/26

Corrected the answer choices: E should read 13/28.

Re: Set 24 question #4 [#permalink]
03 Jun 2012, 06:05

Bunuel wrote:

beckee529 wrote:

not sure if this question has been brought up. i think there is a typo in the answer choices but just wanted to make sure:

A shipment of 8 TV sets contains 2 black and white sets and 6 color sets. If 2 TV sets are to be chosen at random from this shipment, what is the probability that at least 1 of the 2 sets chosen will be a black and white set?

A) 1/7 B) 1/4 C) 5/14 D) 11/28 E) 13/26

Corrected the answer choices: E should read 13/28.

P(at leas one)=1-P(none)=1-6/8*5/7=13/28.

Answer: E.

please clear my understanding

at least one means - either one is black OR Both are black

so p( one is black)= 2/8*6/7 = 3/14

P ( Both are black) = 2/8*1/7 =1/28

so p ( at least one is black ) = 3/14 + 1/28 = 1/4 = Answer B

why is this answer differing when we solve it in the alternate way 1-p( Both color) = P ( at least one black and white )

Re: Set 24 question #4 [#permalink]
03 Jun 2012, 06:12

1

This post received KUDOS

Expert's post

Joy111 wrote:

Bunuel wrote:

beckee529 wrote:

not sure if this question has been brought up. i think there is a typo in the answer choices but just wanted to make sure:

A shipment of 8 TV sets contains 2 black and white sets and 6 color sets. If 2 TV sets are to be chosen at random from this shipment, what is the probability that at least 1 of the 2 sets chosen will be a black and white set?

A) 1/7 B) 1/4 C) 5/14 D) 11/28 E) 13/26

Corrected the answer choices: E should read 13/28.

P(at leas one)=1-P(none)=1-6/8*5/7=13/28.

Answer: E.

please clear my understanding

at least one means - either one is black OR Both are black

so p( one is black)= 2/8*6/7 = 3/14

P ( Both are black) = 2/8*1/7 =1/28

so p ( at least one is black ) = 3/14 + 1/28 = 1/4 = Answer B

why is this answer differing when we solve it in the alternate way 1-p( Both color) = P ( at least one black and white )

The probability that from 2 sets selected exactly one set is black is \(P=2*\frac{2}{8}*\frac{6}{7}=\frac{3}{7}\). We are multiplying by 2 since we can select one blacks set in two ways: {Black, Color} or {Color, Black}.

Re: Set 24 question #4 [#permalink]
03 Jun 2012, 06:49

Bunuel wrote:

Joy111 wrote:

Bunuel wrote:

A shipment of 8 TV sets contains 2 black and white sets and 6 color sets. If 2 TV sets are to be chosen at random from this shipment, what is the probability that at least 1 of the 2 sets chosen will be a black and white set?

A) 1/7 B) 1/4 C) 5/14 D) 11/28 E) 13/26

Corrected the answer choices: E should read 13/28.

P(at leas one)=1-P(none)=1-6/8*5/7=13/28.

Answer: E.

please clear my understanding

at least one means - either one is black OR Both are black

so p( one is black)= 2/8*6/7 = 3/14

P ( Both are black) = 2/8*1/7 =1/28

so p ( at least one is black ) = 3/14 + 1/28 = 1/4 = Answer B

why is this answer differing when we solve it in the alternate way 1-p( Both color) = P ( at least one black and white )

The probability that from 2 sets selected exactly one set is black is \(P=2*\frac{2}{8}*\frac{6}{7}=\frac{3}{7}\). We are multiplying by 2 since we can select one blacks set in two ways: {Black, Color} or {Color, Black}.

Hope it's clear.

+1, certainly will help in understanding many problems , as I thought only in cases where there is repetition , do we multiply , # of ways to arrange { a,a,b,b,b } is 5!/ 3!2!

But now I have a better understanding , even when there is no repetition , but we have more than one ways to select a favorable outcome , we multiply with the # of ways . As shown above . +1

Re: A shipment of 8 TV sets contains 2 black and white sets and [#permalink]
08 Sep 2013, 00:55

i calculated the probability of selecting either 1 or 2 b/w sets its can be denoted as (b,c) or (c,b) or (b,b) = [(2/8)*(6/7)]+[(6/8)*(2/7)]+[2/8*1/7] =(12+12+2)/56 =26/56 or 13/28 _________________

“Confidence comes not from always being right but from not fearing to be wrong.”

Re: A shipment of 8 TV sets contains 2 black and white sets and [#permalink]
26 Oct 2013, 15:46

My attempt to solve it by using Combinations

Total possibilities = 8C2 = 28 Possibilities of getting 1 color and 1 b/w set = 6C1 * 2C1 = 12 Possibilities of getting 0 color and 2 b/white set = 6C0 * 2C2 = 1

Therefore, Probability of atleast 1 b/w = (All possibilities that contains b/w) /Total Possibilities = (12+1)/28 = 13/28

Re: Set 24 question #4 [#permalink]
02 Dec 2013, 12:33

The probability that from 2 sets selected exactly one set is black is \(P=2*\frac{2}{8}*\frac{6}{7}=\frac{3}{7}\). We are multiplying by 2 since we can select one blacks set in two ways: {Black, Color} or {Color, Black}.

Hope it's clear.[/quote]

Bunuel, could you please clarify: In the question statement there is no information that we select without replacement. Shell we assume it and when? Thank you

Re: Set 24 question #4 [#permalink]
03 Dec 2013, 01:08

Expert's post

JullsJulls wrote:

The probability that from 2 sets selected exactly one set is black is \(P=2*\frac{2}{8}*\frac{6}{7}=\frac{3}{7}\). We are multiplying by 2 since we can select one blacks set in two ways: {Black, Color} or {Color, Black}.

Hope it's clear.

Bunuel, could you please clarify: In the question statement there is no information that we select without replacement. Shell we assume it and when? Thank you[/quote]

Usually if it's not clear it's explicitly mentioned. In this question it's clear that we have without replacement case. _________________

Re: A shipment of 8 TV sets contains 2 black and white sets and [#permalink]
20 Apr 2015, 05:50

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. _________________

Type of Visa: You will be applying for a Non-Immigrant F-1 (Student) US Visa. Applying for a Visa: Create an account on: https://cgifederal.secure.force.com/?language=Englishcountry=India Complete...