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 500,000 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:

In a random sample of 80 adults, how many are college graduates?

(1) In the sample, the number of adults who are not college graduates is 3 times the number who are college graduates. (2) In the sample, the number of adults who are not college graduates is 40 more than the number who are college graduates.

Practice Questions Question: 44 Page: 278 Difficulty: 600

Each week we'll be posting several questions from The Official Guide for GMAT® Review, 13th Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution.

We'll be glad if you participate in development of this project: 1. Please provide your solutions to the questions; 2. Please vote for the best solutions by pressing Kudos button; 3. Please vote for the questions themselves by pressing Kudos button; 4. Please share your views on difficulty level of the questions, so that we have most precise evaluation.

In a random sample of 80 adults, how many are college graduates?

(1) In the sample, the number of adults who are not college graduates is 3 times the number who are college graduates. Say the number of college graduates is \(x\), then the number of not college graduates is \(3x\). Thus, \(x+3x=80\). We can find \(x\). Sufficient.

(2) In the sample, the number of adults who are not college graduates is 40 more than the number who are college graduates. Say the number of college graduates is \(x\), then the number of not college graduates is \(x+(x+40)\). Thus, \(x+(x+40)=80\). We can find \(x\). Sufficient.

Re: In a random sample of 80 adults, how many are college [#permalink]

Show Tags

18 Sep 2012, 05:39

Bunuel wrote:

In a random sample of 80 adults, how many are college graduates?

(1) In the sample, the number of adults who are not college graduates is 3 times the number who are college graduates. (2) In the sample, the number of adults who are not college graduates is 40 more than the number who are college graduates.

Since there are 80 adults we don't need to consider non-adults number here. Otherwise, we would have to solve this by 2X2 matrix. Either adults are college graduates (X) or not (Y) Stmt 1) X + Y = 80 Y = 3X these 2 eq can be solved to get the value of X

Stmt 2) Similar way X + Y = 80 Y = 40 + X these 2 eqns can also be solved for value of X

Both statements are sufficient, Hence D
_________________

In a random sample of 80 adults, how many are college graduates?

(1) In the sample, the number of adults who are not college graduates is 3 times the number who are college graduates. (2) In the sample, the number of adults who are not college graduates is 40 more than the number who are college graduates.

Practice Questions Question: 44 Page: 278 Difficulty: 600

Each week we'll be posting several questions from The Official Guide for GMAT® Review, 13th Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution.

We'll be glad if you participate in development of this project: 1. Please provide your solutions to the questions; 2. Please vote for the best solutions by pressing Kudos button; 3. Please vote for the questions themselves by pressing Kudos button; 4. Please share your views on difficulty level of the questions, so that we have most precise evaluation.

Thank you!

Lets say college going graduate is X and college not going graduate is Y

form question X + Y = 80. Option 1: Y = 3X so, X + 3X = 80 leads to X = 20. Therefore option 1 is sufficient to answer the question. Option 2: Y - X = 40. so, 2Y = 120, leads to Y = 60 and X = 20. therefore option 2 is sufficient to anser the question.

Therefor from above both the options are individually sufficient to answer the question => "D" is the correct choice.

In a random sample of 80 adults, how many are college graduates?

(1) In the sample, the number of adults who are not college graduates is 3 times the number who are college graduates. Say the number of college graduates is \(x\), then the number of not college graduates is \(3x\). Thus, \(x+3x=80\). We can find \(x\). Sufficient.

(2) In the sample, the number of adults who are not college graduates is 40 more than the number who are college graduates. Say the number of college graduates is \(x\), then the number of not college graduates is \(x+(x+40)\). Thus, \(x+(x+40)=80\). We can find \(x\). Sufficient.

Answer: D.

Kudos points given to everyone with correct solution. Let me know if I missed someone.
_________________

In a random sample of 80 adults, how many are college graduates?

(1) In the sample, the number of adults who are not college graduates is 3 times the number who are college graduates. (2) In the sample, the number of adults who are not college graduates is 40 more than the number who are college graduates.

Practice Questions Question: 44 Page: 278 Difficulty: 600

Basically, we need to solve for x + y = 80, so we need to solve for 2 unknowns, either by solving for one of them or for both at the same time.

1) This statement tells us that x + 3x = 80, we have one equation and one unknown, so it's sufficient. 2) This tells us that (y + 40) + y = 80, so again we have 1 unknown and 1 equation, so we can solve it. Sufficient.

In a random sample of 80 adults, how many are college graduates?

(1) In the sample, the number of adults who are not college graduates is 3 times the number who are college graduates. (2) In the sample, the number of adults who are not college graduates is 40 more than the number who are college graduates.

We need to determine the number of college graduates in a sample of 80 adults. Because some of the 80 adults are college graduates, while others are not, let’s define two variables:

c = the number of adults who are college graduates

n = the number of adults who are not college graduates

Since there are 80 adults in the random sample, we can create the following equation:

c + n = 80

Statement One Alone:

In the sample, the number of adults who are not college graduates is 3 times the number who are college graduates.

From statement one we can say:

n = 3c

Since n = 3c, we can plug 3c for n into the equation c + n = 80.

c + 3c = 80

4c = 80

c = 20

Thus, there are 20 college graduates. Statement one is sufficient to answer the question. We can eliminate answer choices B, C, and E.

Statement Two Alone:

In the sample, the number of adults who are not college graduates is 40 more than the number who are college graduates.

From statement two, we can say:

n = 40 + c

Since 40 + c = n, we can substitute 40 + c for n into the equation c + n = 80.

c + 40 + c = 80

2c = 40

c = 20

There are 20 college graduates.

Statement two is also sufficient to answer the question.

The answer is D.
_________________

Jeffrey Miller Scott Woodbury-Stewart Founder and CEO

gmatclubot

Re: In a random sample of 80 adults, how many are college
[#permalink]
25 Aug 2016, 15:10

Its been long time coming. I have always been passionate about poetry. It’s my way of expressing my feelings and emotions. And i feel a person can convey...

Written by Scottish historian Niall Ferguson , the book is subtitled “A Financial History of the World”. There is also a long documentary of the same name that the...

Post-MBA I became very intrigued by how senior leaders navigated their career progression. It was also at this time that I realized I learned nothing about this during my...