DS - % of

This topic has expert replies
User avatar
Legendary Member
Posts: 1665
Joined: Thu Nov 03, 2011 7:04 pm
Thanked: 165 times
Followed by:70 members

DS - % of

by karthikpandian19 » Mon Jun 11, 2012 6:48 pm
Of the students at School X who major in history, what percent live on campus?

50 students at School X major in history and live on campus.
At School X, 10% of the students major in history.
Regards,
Karthik
The source of the questions that i post from JUNE 2013 is from KNEWTON

---If you find my post useful, click "Thank" :) :)---
---Never stop until cracking GMAT---
Source: — Data Sufficiency |

User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Tue Jun 12, 2012 2:56 am
karthikpandian19 wrote:Of the students at School X who major in history, what percent live on campus?

50 students at School X major in history and live on campus.
At School X, 10% of the students major in history.
Statements 1 and 2 combined:
Case 1: total students = 1000.
History students = .1(1000) = 100.
Since 50 history students live on campus, (on campus)/(total history) = 50/100 = 50%.

Case 2: total students = 2000.
History students = .1(2000) = 200.
Since 50 history students live on campus, (on campus)/(total history) = 50/200 = 25%.

Since different percentages are possible, the two statements combined are INSUFFICIENT.

The correct answer is E.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

User avatar
Master | Next Rank: 500 Posts
Posts: 210
Joined: Thu Mar 08, 2012 11:24 pm
Thanked: 62 times
Followed by:3 members

by niketdoshi123 » Tue Jun 12, 2012 2:59 am
karthikpandian19 wrote:Of the students at School X who major in history, what percent live on campus?

a)50 students at School X major in history and live on campus.

b)At School X, 10% of the students major in history.
What the question stem is asking
HC/H*100

So we need to find 2 things
1)the number of students at School X who major in history:(H)
2)The number of students at School X who major in history live on campus:(HC)

statement 1 is INSUFFICIENT
As the total number of students at School X who major in history is not known.
HC= 50
H=?
statement 2 is INSUFFICIENT
As the number of students at School X is not known.
HC=?
H=10% of students(?)

By Combining both the statements
HC=50
H=10% of students( still no exact value).
Hence INSUFFICIENT

So the answer is E

User avatar
Legendary Member
Posts: 1665
Joined: Thu Nov 03, 2011 7:04 pm
Thanked: 165 times
Followed by:70 members

by karthikpandian19 » Tue Jun 12, 2012 5:22 am
From statement 1, i understood that 50 students is equal to HC and H? Can you clarify? So in my opinion statement 1 is sufficient
niketdoshi123 wrote:
karthikpandian19 wrote:Of the students at School X who major in history, what percent live on campus?

a)50 students at School X major in history and live on campus.

b)At School X, 10% of the students major in history.
What the question stem is asking
HC/H*100

So we need to find 2 things
1)the number of students at School X who major in history:(H)
2)The number of students at School X who major in history live on campus:(HC)

statement 1 is INSUFFICIENT
As the total number of students at School X who major in history is not known.
HC= 50
H=?
statement 2 is INSUFFICIENT
As the number of students at School X is not known.
HC=?
H=10% of students(?)

By Combining both the statements
HC=50
H=10% of students( still no exact value).
Hence INSUFFICIENT

So the answer is E
Regards,
Karthik
The source of the questions that i post from JUNE 2013 is from KNEWTON

---If you find my post useful, click "Thank" :) :)---
---Never stop until cracking GMAT---