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

It is currently 19 Oct 2019, 20:20

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 cylinder with a volume of 80π is altered so that its radius becomes

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

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58445
A cylinder with a volume of 80π is altered so that its radius becomes  [#permalink]

Show Tags

New post 29 Aug 2018, 01:41
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

80% (01:25) correct 20% (00:47) wrong based on 47 sessions

HideShow timer Statistics

GMAT Club Legend
GMAT Club Legend
User avatar
D
Joined: 18 Aug 2017
Posts: 5021
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
GMAT ToolKit User Premium Member
Re: A cylinder with a volume of 80π is altered so that its radius becomes  [#permalink]

Show Tags

New post 29 Aug 2018, 01:50
A cylinder with a volume of 80π is altered so that its radius becomes half of the original radius and its height becomes double the original height. What is the volume of the altered cylinder?


A. 160π160π

B. 80π80π

C. 40π40π

D. 20π20π

E. 10π10π

original area : 3.14*r^2*h: 80*3.14
We can deduce
=> r^2*h: 80-----(1)

Area to be found: 3.14*(r/2)^2*2h -----(2)

substitute value from (1) in (2)
=> 3.14*(80*2)/4
=> answer 40 *3.14 option C
VP
VP
User avatar
D
Status: Learning stage
Joined: 01 Oct 2017
Posts: 1013
WE: Supply Chain Management (Energy and Utilities)
A cylinder with a volume of 80π is altered so that its radius becomes  [#permalink]

Show Tags

New post 29 Aug 2018, 02:01
Bunuel wrote:
A cylinder with a volume of 80π is altered so that its radius becomes half of the original radius and its height becomes double the original height. What is the volume of the altered cylinder?


A. \(160\pi\)

B. \(80\pi\)

C. \(40\pi\)

D. \(20\pi\)

E. \(10\pi\)


Given, \(r^'\)=\(\frac{r}{2}\) and \(h^'=2h\)
Volume of altered cylinder= \(\pi*r^'^2*h^'\)=\(\pi*(\frac{r}{2})^2*2h\)=\(\frac{1}{2}*\pi*r^2*h)\)=\(\frac{1}{2}*80\pi\)= \(40\pi\)

Ans. (C)
_________________
Regards,

PKN

Rise above the storm, you will find the sunshine
Target Test Prep Representative
User avatar
G
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2815
Re: A cylinder with a volume of 80π is altered so that its radius becomes  [#permalink]

Show Tags

New post 03 Sep 2018, 19:05
Bunuel wrote:
A cylinder with a volume of 80π is altered so that its radius becomes half of the original radius and its height becomes double the original height. What is the volume of the altered cylinder?


A. \(160\pi\)

B. \(80\pi\)

C. \(40\pi\)

D. \(20\pi\)

E. \(10\pi\)


We can let r = the original radius and h = the original height of the cylinder. So we have:

πr^2h = 80π

r^2h = 80

Now, we can make up a convenient number for r and calculate h. For example, we can let r = 4, so we have:

4^2h = 80

16h = 80

h = 5

Now, let’s halve the radius and double the height, so the new radius is 2 and the new height is 10. Therefore, the new volume is:

π x 2^2 x 10 = 40π

Answer: C
_________________

Jeffrey Miller

Head of GMAT Instruction

Jeff@TargetTestPrep.com
TTP - Target Test Prep Logo
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

GMAT Club Bot
Re: A cylinder with a volume of 80π is altered so that its radius becomes   [#permalink] 03 Sep 2018, 19:05
Display posts from previous: Sort by

A cylinder with a volume of 80π is altered so that its radius becomes

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





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