GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 22 Oct 2018, 09:36

### 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
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

# In a certain senior class, 72 percent of the male students and 80 perc

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Intern
Joined: 11 Jul 2010
Posts: 24
In a certain senior class, 72 percent of the male students and 80 perc  [#permalink]

### Show Tags

17 Sep 2010, 21:48
00:00

Difficulty:

55% (hard)

Question Stats:

60% (00:24) correct 40% (01:08) wrong based on 30 sessions

### HideShow timer Statistics

In a certain senior class, 72 percent of the male students and 80 percent of the female students have applied to college. What fraction of the students in the class are male?

(1) There are 840 students in the senior class.
(2) 75 percent of the students in the senior class have applied to college.

OPEN DISCUSSION OF THIS QUESTION IS HERE: http://gmatclub.com/forum/in-a-certain- ... 28279.html

--== Message from the GMAT Club Team ==--

THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION.
This discussion does not meet community quality standards. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Math Expert
Joined: 02 Sep 2009
Posts: 50041
Re: In a certain senior class, 72 percent of the male students and 80 perc  [#permalink]

### Show Tags

17 Sep 2010, 21:54
In a certain senior class, 72 percent of the male students and 80 percent of the female students have applied to college. What fraction of the students in the senior class are male?

This is weighted average question.

Q: $$\frac{m}{m+f}=?$$

(1) There are 840 students in the senior class --> $$m+f=840$$. Stem info is useless. Not sufficient.

(2) 75 percent of the students in the senior class have applied to college --> $$0.72m+0.8f=0.75(m+f)$$ --> $$3m=5f$$ --> $$\frac{m}{f}=\frac{5}{3}$$ --> $$\frac{m}{m+f}=\frac{5}{8}$$. Sufficient.

Answer: B.
_________________
Intern
Joined: 27 Jul 2010
Posts: 14
Location: Bangalore
Re: In a certain senior class, 72 percent of the male students and 80 perc  [#permalink]

### Show Tags

17 Sep 2010, 21:59
rgtiwari wrote:
Ina a certain senior class, 72% of the male students and 80% of the female students have applied to the college.What fractions of the students in the senior class are male?

a) There are 840 students in the senior class.
b) 75% of the stunts in the senior class have applied to the college.

We need to find what fraction of students are male in the senior class..

a-> clearly insuff
b-> 75% have applied to college
Lets take x number of male and y no of female students are thr.

so,

(72/100)X | (80/100)Y=(75/100)(X+Y)
5Y=3X

b-> sufficient..
_________________

Nothing is free.. You 've to earn it!!!

Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 8406
Location: Pune, India
Re: In a certain senior class, 72 percent of the male students and 80 perc  [#permalink]

### Show Tags

09 Nov 2010, 06:07
1
anilnandyala wrote:
in a certain class 72% of the male students & 80% of the female students have applied to college what fraction of the students in the senior college are male?
1 there are 840 students in the senior class
2 75% students in the senior class have applied to the college

(I am assuming that 'senior college' in question stem is the same as 'senior class')
This is a question of weighted averages.

Statement 1: Total students is 840 but we do not know how many of them are male and how many are female.

Statement 2: 75% of total have applied to college. 72% of males have applied and 80% of females have applied. The weighted average of 72% and 80% is known to be 75%.

_______________________
72% 75% 80%

Diff between 72 and 75 is 3 and that between 75 and 80 is 5 hence males:females ratio is 5:3.

Hence 5/8 of the students in senior class are males.
Statement 2 is sufficient. Answer is (B).
_________________

Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >

GMAT self-study has never been more personalized or more fun. Try ORION Free!

Current Student
Joined: 31 Oct 2011
Posts: 190
Re: In a certain senior class, 72 percent of the male students and 80 perc  [#permalink]

### Show Tags

04 Jan 2012, 02:24
I know how to solve these questions on DS. I know the rule actually but dont know step by step solution so would really appreciate if someone can provide that. Thanks
Attachments

GP03.jpg [ 127.58 KiB | Viewed 1415 times ]

Manager
Joined: 14 Mar 2011
Posts: 68
Re: In a certain senior class, 72 percent of the male students and 80 perc  [#permalink]

### Show Tags

04 Jan 2012, 03:49
Hi

Says M-Present Males & F-Present Females .. The statement we have senior class have 0.75M+.80F-

Total Students lot = M+F

Statement 1- M+F = 840 - Not Sufficient .. to determine fraction of M

Statement 2 - means 0.75 (M+F) = 0.75M+0.80 F

WE can calculate M & F relation

So M fraction can be workout as ------------ M/ (M+F) by converting F in terms of M from Statement 2 .

So B is right Answer
Manager
Joined: 13 May 2011
Posts: 245
WE 1: IT 1 Yr
WE 2: Supply Chain 5 Yrs
Re: In a certain senior class, 72 percent of the male students and 80 perc  [#permalink]

### Show Tags

04 Jan 2012, 07:53
from statement 2 we get: 5F=3M
how B is sufficient to answer: M/(M+F)?
Manager
Joined: 13 May 2011
Posts: 245
WE 1: IT 1 Yr
WE 2: Supply Chain 5 Yrs
Re: In a certain senior class, 72 percent of the male students and 80 perc  [#permalink]

### Show Tags

04 Jan 2012, 08:00
sorry for the last post. I got it.
Manager
Joined: 29 Jul 2011
Posts: 92
Location: United States
Re: In a certain senior class, 72 percent of the male students and 80 perc  [#permalink]

### Show Tags

06 Jan 2012, 19:19
Hi, let me simplify this for you.

Have you read distribution charts from MGMAT word problem book? You need to form a chart like this:

Male Female Total
Applied
not Applied

Let total be 100 (100%).
Let total males = y, females = 100-y.

You get applied + Males = 0.72y (72%)
You get applied +Females = 0.80(100-y) (80%)

Rephrase: y = ?

Now, lets look at the statements.
1. Total given, no use since we don't know male/female distribution. Insuff.
2. Applied = 75% total. So, we get 0.72y + 0.8(100-y) = 75. solving gives us y. Suff

B.
_________________

I am the master of my fate. I am the captain of my soul.
Please consider giving +1 Kudos if deserved!

DS - If negative answer only, still sufficient. No need to find exact solution.
PS - Always look at the answers first
CR - Read the question stem first, hunt for conclusion
SC - Meaning first, Grammar second
RC - Mentally connect paragraphs as you proceed. Short = 2min, Long = 3-4 min

Math Expert
Joined: 02 Sep 2009
Posts: 50041
Re: In a certain senior class, 72 percent of the male students and 80 perc  [#permalink]

### Show Tags

23 Nov 2017, 08:13
In a certain senior class, 72 percent of the male students and 80 percent of the female students have applied to college. What fraction of the students in the senior class is male?

Question: $$\frac{m}{m+f}=?$$ (so we are asked about #3)

(1) There are 840 students in the senior class --> $$m+f=840$$. Useless info. Not sufficient.

(2) 75 percent of the students in the senior class have applied to college. We know 2 from the stem and 1 from this statement, sufficient to get 3. Just to illustrate: $$0.72m+0.8f=0.75(m+f)$$ --> $$3m=5f$$ --> $$\frac{m}{f}=\frac{5}{3}$$ --> $$\frac{m}{m+f}=\frac{5}{8}$$. Sufficient.

Answer: B.

OPEN DISCUSSION OF THIS QUESTION IS HERE: http://gmatclub.com/forum/in-a-certain- ... 28279.html

--== Message from the GMAT Club Team ==--

THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION.
This discussion does not meet community quality standards. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.

_________________
Re: In a certain senior class, 72 percent of the male students and 80 perc &nbs [#permalink] 23 Nov 2017, 08:13
Display posts from previous: Sort by

# In a certain senior class, 72 percent of the male students and 80 perc

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.