A circular mat with diameter 20 inches

This topic has expert replies
User avatar
Master | Next Rank: 500 Posts
Posts: 421
Joined: Sun Apr 17, 2011 4:27 am
Location: India
Thanked: 6 times
Followed by:2 members
GMAT Score:620

A circular mat with diameter 20 inches

by vinni.k » Wed Jan 02, 2013 2:50 am
A circular mat with diameter 20 inches is placed on a square tabletop, each of whose sides is 24 inch long. Which of the following is closest to the fraction of the tabletop covered by the mat ?

A. 5/12
B. 2/5
C. 1/2
D. 3/4
E. 5/6

Answer is C

Thanks & Regards
Vinni

Legendary Member
Posts: 512
Joined: Mon Jun 18, 2012 11:31 pm
Thanked: 42 times
Followed by:20 members

by sana.noor » Wed Jan 02, 2013 5:47 am
The area of the circle is calculated as C = pie(r^2) as the diameter is 20 thus the radius will be 10 therefore C = pie (10^2) = 314
the area of the square is calculated as S^2, as each side of the square table is 24 inch long thus the area of the square will be 24^2 = 576
The area that is covered by the circular mat is 314/576 = 54% or nearly 1/2....the answer is C
Work hard in Silence, Let Success make the noise.

If you found my Post really helpful, then don't forget to click the Thank/follow me button. :)

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 » Wed Jan 02, 2013 10:33 pm
vinni.k wrote:A circular mat with diameter 20 inches is placed on a square tabletop, each of whose sides is 24 inch long. Which of the following is closest to the fraction of the tabletop covered by the mat ?

A. 5/12
B. 2/5
C. 1/2
D. 3/4
E. 5/6

Answer is C
Area of the circular mat = �r² ≈ 3*10².
Area of the table = s² = 24².
Mat/table = (3*10*10)/(24*24) = (3*25*4)(3*24*8) ≈ 1/2.

The correct answer is C.
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

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 1462
Joined: Thu Apr 09, 2015 9:34 am
Location: New York, NY
Thanked: 39 times
Followed by:22 members

by Jeff@TargetTestPrep » Thu Dec 14, 2017 9:18 am
vinni.k wrote:A circular mat with diameter 20 inches is placed on a square tabletop, each of whose sides is 24 inch long. Which of the following is closest to the fraction of the tabletop covered by the mat ?

A. 5/12
B. 2/5
C. 1/2
D. 3/4
E. 5/6
Since the diameter of the mat is 20 inches, the radius is 10 inches. The area of the mat is:

area = πr^2 = π(10)^2 = 3.14 x 100 = 314 square inches

Since each side of the square tabletop is 24 inches long, the area is:

area = side^2 = 24 x 24 = 576 square inches

Thus, the fraction of the table covered by the mat is 314/576 = 157/288

157/288 is about 160/290 = 16/29, which is about 1/2.

Answer: C

Jeffrey Miller
Head of GMAT Instruction
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews