Summer is Coming! Join the Game of Timers Competition to Win Epic Prizes. Registration is Open. Game starts Mon July 1st.

It is currently 20 Jul 2019, 17:20

Close

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

A circle with a radius of 4 feet is cut from a piece of sheet metal

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Tuck School Moderator
User avatar
P
Status: Valar Dohaeris
Joined: 31 Aug 2016
Posts: 304
GMAT 1: 700 Q49 V37
Reviews Badge
A circle with a radius of 4 feet is cut from a piece of sheet metal  [#permalink]

Show Tags

New post 21 Aug 2018, 19:29
1
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

61% (01:42) correct 39% (01:53) wrong based on 43 sessions

HideShow timer Statistics


A circle with a radius of 4 feet is cut from a piece of sheet metal with uniform thickness. The circle weighs 20 pounds. If another circle is cut from the same sheet and weighs 60 pounds, then its radius is closest to which of the following?

A. 6 feet
B. 7 feet
C. 8 feet
D. 9 feet
E. 10 feet

_________________
VP
VP
User avatar
D
Status: Learning stage
Joined: 01 Oct 2017
Posts: 1028
WE: Supply Chain Management (Energy and Utilities)
Re: A circle with a radius of 4 feet is cut from a piece of sheet metal  [#permalink]

Show Tags

New post 21 Aug 2018, 20:09
PeepalTree wrote:
A circle with a radius of 4 feet is cut from a piece of sheet metal with uniform thickness. The circle weighs 20 pounds. If another circle is cut from the same sheet and weighs 60 pounds, then its radius is closest to which of the following?

A. 6 feet
B. 7 feet
C. 8 feet
D. 9 feet
E. 10 feet


Weight is calculated from the area.
Given, 20 pounds corresponds to an area of \(\pi(4)^2\)
So area of the circle with unit pound(1 pound)=\(\frac{\pi(4)^2}{20}\)

Since the circle with weight 60 pounds is cut from the same metal sheet we can correlate the unit pounds of the first circle with the second circle.
Hence, area of the circle with 60 pounds=\(\frac{\pi(4)^2}{20}*60\)=\(48\pi\)
So, radius of the circle=\(\sqrt{\frac{48\pi}{\pi}}\)=\(\sqrt{48}\approx{7}\)

Ans. (B)
_________________
Regards,

PKN

Rise above the storm, you will find the sunshine
e-GMAT Representative
User avatar
V
Joined: 04 Jan 2015
Posts: 2943
Re: A circle with a radius of 4 feet is cut from a piece of sheet metal  [#permalink]

Show Tags

New post 21 Aug 2018, 23:37

Solution



Given:
    • A circle with a radius of 4 feet is cut from a piece of sheet metal with uniform thickness.
    • The circle weighs 20 pounds.
    • Another circle is cut from the same sheet and weighs 60 pounds.

To find:
    • The radius of the second circle.

Approach and Working:
The weight of the second circle is 3 times the weight of the first circle.
    • Because of uniform thickness, its area will also be 3 times of the area of the first circle.

Now, the area of the first circle = π x 4 x 4 = 16π
    • Hence, the area of the second circle = 3 x 16π = 48π
    • As the area is 48π, the radius should be very close to 7.

Hence, the correct answer is option B.

Answer: B

Image

_________________
GMAT Club Bot
Re: A circle with a radius of 4 feet is cut from a piece of sheet metal   [#permalink] 21 Aug 2018, 23:37
Display posts from previous: Sort by

A circle with a radius of 4 feet is cut from a piece of sheet metal

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





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne