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:

Of all the students in a certain dormitory, 1/2 are first-ye [#permalink]

Show Tags

27 Dec 2009, 10:47

5

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

25% (medium)

Question Stats:

77% (02:35) correct
23% (01:47) wrong based on 321 sessions

HideShow timer Statistics

Of all the students in a certain dormitory, 1/2 are first-year students and the rest are second-year students. If 4/5 of the first-year students have not declared a major and if the fraction of second-year students who have declared a major is 3 times the fraction of first-year students who have declared a major, what fraction of all the students in the dormitory are second-year students who have not declared a major?

I think you dropped a fraction when you typed/copied this in. Working backward from the spoiler answer, I'm thinking the second sentence should read as follows? Please confirm.

"If 4/5 of the first-year students have not declared a major ..."
_________________

Emily Sledge | Manhattan GMAT Instructor | St. Louis

Of all the students in a certain dormitory, 1/2 are first-year students and the rest are second-year students. If 4/5 of the first-year students have not declared a major and if the fraction of second-year students who have declared a major is 3 times the fraction of first-year students who have declared a major, what fraction of all the students in the dormitory are second-year students who have not declared a major?

\(\frac{4}{5}x\) of the first-year students have not declared a major --> \(\frac{1}{5}x\) declared;

Second-year students who have declared a major is 3 times the fraction of first-year students who have declared a major =\(\frac{3}{5}x\) --> who have not \(\frac{2}{5}x\);

Re: Of all the students in a certain dormitory, 1/2 are first-year student [#permalink]

Show Tags

12 Aug 2011, 15:23

I think the answer choices you have provided because the answer cannot be greater than one.

Here is an easy way to think about this is by picking "smart" numbers. Let's pick 50 for the first half of students who are 1st years and 50 for the other half who are 2nd year. We know that 4/5 of the 1st years have not declared a major so that gives us 50*4/5=40, so 10 have declared a major. We also know that the number of 2nd year that have not declared a major = 3 times the # of 1st year who have declared a major. This gives us 3*10=30

The question asks for fraction of 2nd years who have not declared a major over the total students. 30 have declared a major out of the 2nd year so 20 have not. Since we have 100 students (50+50), the answer is 20/100 or 1/5.

You can run a search on the web and you will find this question without the correct answer choices.

Re: Of all the students in a certain dormitory, 1/2 are first-ye [#permalink]

Show Tags

01 Sep 2014, 19:09

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: Of all the students in a certain dormitory, 1/2 are first-ye [#permalink]

Show Tags

28 Apr 2016, 23:06

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.
_________________

Of all the students in a certain dormitory, 1/2 are first-year students and the rest are second-year students. If 4/5 of the first-year students have not declared a major and if the fraction of second-year students who have declared a major is 3 times the fraction of first-year students who have declared a major, what fraction of all the students in the dormitory are second-year students who have not declared a major?

A. 151 B. 51 C. 154 D. 31 E. 52

Say there are in all 100 students. Use a matrix: 50 are first year and 50 are second year students.

........................Major Dec................Major not dec..............Total First Year............................................................................50 Second Yr...........................................................................50 Total

4/5 * 50 = 40 not declared major first year students.

........................Major Dec................Major not dec..............Total First Year................10..................................40....................50 Second Yr...........................................................................50 Total

second-year students who have declared a major is 3 times the fraction of first-year students who have declared a major

........................Major Dec................Major not dec..............Total First Year................10..................................40.....................50 Second Yr...............30..................................20......................50 Total

So second year students who've not declared a major is 20/100 = 1/5

Re: Of all the students in a certain dormitory, 1/2 are first-year student [#permalink]

Show Tags

27 Jun 2016, 05:51

1

This post received KUDOS

The answer choices provided are not correct!

I solved the question using LCM method. The solution is given below:

Assume the total number of stuents to be 30, LCM(2,3,5)

Now, as per the given info, half the students are 1st year. Therefore, there are 15 students each in 1st and 2nd year. We can further calculate the students who have selected majors in 1st year and second year. And, finally we can calculate the fraction for answering the question

I solved the question using LCM method. The solution is given below:

Assume the total number of stuents to be 30, LCM(2,3,5)

Now, as per the given info, half the students are 1st year. Therefore, there are 15 students each in 1st and 2nd year. We can further calculate the students who have selected majors in 1st year and second year. And, finally we can calculate the fraction for answering the question

After days of waiting, sharing the tension with other applicants in forums, coming up with different theories about invites patterns, and, overall, refreshing my inbox every five minutes to...

I was totally freaking out. Apparently, most of the HBS invites were already sent and I didn’t get one. However, there are still some to come out on...

In early 2012, when I was working as a biomedical researcher at the National Institutes of Health , I decided that I wanted to get an MBA and make the...