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:

Of the 300 subjects who participated in an experiment using [#permalink]
08 Jun 2012, 00:16

8

This post received KUDOS

43

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

95% (hard)

Question Stats:

59% (03:59) correct
41% (03:27) wrong based on 881 sessions

Of the 300 subjects who participated in an experiment using virtual-reality therapy to reduce their fear of heights, 40 percent experienced sweaty palms, 30 percent experienced vomiting, and 75 percent experienced dizziness. If all of the subjects experienced at least one of these effects and 35 percent of the subjects experienced exactly two of these effects, how many of the subjects experienced only one of these effects?

Re: Of the 300 subjects who participated in an experiment using [#permalink]
08 Jun 2012, 00:57

25

This post received KUDOS

8

This post was BOOKMARKED

Quote:

Of the 300 subjects who participated in an experiment using virtual-reality therapy to reduce their fear of heights, 40 percent experienced sweaty palms, 30 percent experienced vomiting, and 75 percent experienced dizziness. If all of the subjects experienced at least one of these effects and 35 percent of the subjects experienced exactly two of these effects, how many of the subjects experienced only one of these effects?

A. 105 B. 125 C. 130 D. 180 E. 195

Hi,

We know, \(A\cup B\cup C = A+B+C-A\cap B-B\cap C-C\cap A +A\cap B\cap C\) where \(A = 40%\) \(B = 30%\) \(C = 75%\) As per the attached Venn diagram, \(A\cup B\cup C=100%\)

\(A\cap B+B\cap C+C\cap A=\)Exactly two - 3x (assuming \(A\cap B\cap C=x\)) \(=35-3x\) Thus, \(100= 40+30+75-(35-3x)+x\) or \(x = 5%\)

Thus, subjects expriencing only one effect = 100% - (subjects expriencing only two effects) - (subjects expriencing all effects) or subjects expriencing only one effect = 100 - 35 - 5 = 60%

Adding equations (1), (2) and (3) we get x+y+z+2(p+q+r+w)+w=435 subtract equation (a) from above equation we get p+q+r+2w = 135 given p+q+r = 105 (35% of 300)

so w =15 and p+q+r+w = 120

substitute value of above equation in (a) gets x+y+z = 180

Piyush K ----------------------- Our greatest weakness lies in giving up. The most certain way to succeed is to try just one more time. ― Thomas A. Edison Don't forget to press--> Kudos My Articles: 1. WOULD: when to use?| 2. All GMATPrep RCs (New) Tip: Before exam a week earlier don't forget to exhaust all gmatprep problems specially for "sentence correction".

Re: Of the 300 subjects who participated in an experiment using [#permalink]
15 Aug 2013, 10:18

1

This post received KUDOS

Quote:

So Group 1 + Group 2 + Group 3 - 2-group overlaps * 2 - 3-group overlaps * 3 is our answer

i dont understand why Vandygrad multiplies 2 gr overlaps by 2 and 3 gr overlaps by 3? dont we need to minus 3 times "exactly 2 gr" overlaps and once "3 gr" overlaps?

Re: Of the 300 subjects who participated in an experiment using [#permalink]
15 Aug 2013, 13:25

3

This post received KUDOS

1

This post was BOOKMARKED

macjas wrote:

Of the 300 subjects who participated in an experiment using virtual-reality therapy to reduce their fear of heights, 40 percent experienced sweaty palms, 30 percent experienced vomiting, and 75 percent experienced dizziness. If all of the subjects experienced at least one of these effects and 35 percent of the subjects experienced exactly two of these effects, how many of the subjects experienced only one of these effects?

A. 105 B. 125 C. 130 D. 180 E. 195

exactly two = A+B+C-2(A n B n C)-(A u B u C) OR, 35 = 40+30+75 - 2(A n B n C) - 100 OR, (A n B n C) = 5% = 5% OF 300 = 15

Exactly 3 = 15 Exactly 2 = 35% of 300 = 105 So exactly one = 300 -(15+105) = 180 (Answer) _________________

Re: Of the 300 subjects who participated in an experiment using [#permalink]
16 Aug 2013, 01:00

1

This post received KUDOS

Expert's post

Galiya wrote:

Quote:

So Group 1 + Group 2 + Group 3 - 2-group overlaps * 2 - 3-group overlaps * 3 is our answer

i dont understand why Vandygrad multiplies 2 gr overlaps by 2 and 3 gr overlaps by 3? dont we need to minus 3 times "exactly 2 gr" overlaps and once "3 gr" overlaps?

Re: Of the 300 subjects who participated in an experiment using [#permalink]
18 Aug 2013, 04:53

1

This post received KUDOS

Galiya wrote:

Quote:

So Group 1 + Group 2 + Group 3 - 2-group overlaps * 2 - 3-group overlaps * 3 is our answer

i dont understand why Vandygrad multiplies 2 gr overlaps by 2 and 3 gr overlaps by 3? dont we need to minus 3 times "exactly 2 gr" overlaps and once "3 gr" overlaps?

The reason is simple; you do not want to include any of the common elements. In this case there are three elements;

So when you add A and B you are counting the exactly2 common elements twice once with A and once with B ; so considering other combinations we subtract 2gr overlaps twice and not thrice. _________________

--It's one thing to get defeated, but another to accept it.

Re: Of the 300 subjects who participated in an experiment using [#permalink]
19 Aug 2013, 11:55

3

This post received KUDOS

macjas wrote:

Of the 300 subjects who participated in an experiment using virtual-reality therapy to reduce their fear of heights, 40 percent experienced sweaty palms, 30 percent experienced vomiting, and 75 percent experienced dizziness. If all of the subjects experienced at least one of these effects and 35 percent of the subjects experienced exactly two of these effects, how many of the subjects experienced only one of these effects?

A. 105 B. 125 C. 130 D. 180 E. 195

100%=40%+30%+75%-35%-2*x or, 2x=10% or, x=5% Experienced only one of these effects=100%-35%-5%=60% By the way, 100%=300 or, 1%=300/100 or, 60%=300*60/100=180 So, the best answer is (D). posted By mannan mian

So Group 1 + Group 2 + Group 3 - 2-group overlaps * 2 - 3-group overlaps * 3 is our answer = 120 + 90 + 225 - 105*2 - 15*3 = 435 - 210 - 45 = 180

Can someone explain how we get the formula highlighted in red above? Why do we multiply the 2-group overlaps and 3-group overlaps by 2 and 3 respectively? I didn't get that part. Thanks.

So Group 1 + Group 2 + Group 3 - 2-group overlaps * 2 - 3-group overlaps * 3 is our answer = 120 + 90 + 225 - 105*2 - 15*3 = 435 - 210 - 45 = 180

Can someone explain how we get the formula highlighted in red above? Why do we multiply the 2-group overlaps and 3-group overlaps by 2 and 3 respectively? I didn't get that part. Thanks.

Re: Of the 300 subjects who participated in an experiment using [#permalink]
01 Jul 2014, 09:10

cyberjadugar wrote:

Quote:

Of the 300 subjects who participated in an experiment using virtual-reality therapy to reduce their fear of heights, 40 percent experienced sweaty palms, 30 percent experienced vomiting, and 75 percent experienced dizziness. If all of the subjects experienced at least one of these effects and 35 percent of the subjects experienced exactly two of these effects, how many of the subjects experienced only one of these effects?

A. 105 B. 125 C. 130 D. 180 E. 195

Hi,

We know, \(A\cup B\cup C = A+B+C-A\cap B-B\cap C-C\cap A +A\cap B\cap C\) where \(A = 40%\) \(B = 30%\) \(C = 75%\) As per the attached Venn diagram, \(A\cup B\cup C=100%\)

\(A\cap B+B\cap C+C\cap A=\)Exactly two - 3x (assuming \(A\cap B\cap C=x\)) \(=35-3x\) Thus, \(100= 40+30+75-(35-3x)+x\) or \(x = 5%\)

Thus, subjects expriencing only one effect = 100% - (subjects expriencing only two effects) - (subjects expriencing all effects) or subjects expriencing only one effect = 100 - 35 - 5 = 60%

60% of 300 = 180

Answer is (D)

Regards,

One correction: In 100= 40+30+75-(35-3x)+x, it should be (35+3x)

gmatclubot

Re: Of the 300 subjects who participated in an experiment using
[#permalink]
01 Jul 2014, 09:10

MBA Acceptance Rate by Country Most top American business schools brag about how internationally diverse they are. Although American business schools try to make sure they have students from...

McCombs Acceptance Rate Analysis McCombs School of Business is a top MBA program and part of University of Texas Austin. The full-time program is small; the class of 2017...