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

 It is currently 17 Oct 2019, 19:26

### 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

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

# Obra drove 160π meters along a circular track. If the area enclosed by

Author Message
TAGS:

### Hide Tags

Intern
Joined: 17 Mar 2016
Posts: 7
Obra drove 160π meters along a circular track. If the area enclosed by  [#permalink]

### Show Tags

Updated on: 07 Jul 2016, 21:55
1
00:00

Difficulty:

15% (low)

Question Stats:

83% (01:48) correct 17% (02:27) wrong based on 48 sessions

### HideShow timer Statistics

Obra drove 160π meters along a circular track. If the area enclosed by the circular track on which she drove is 57,600π square meters, what percentage of the circular track did Obra drive?

A. 6.67%
B. 12.5%
C. 18.75%
D. 25%
E. 33.3%

Originally posted by EthosGMAT on 07 Jul 2016, 20:12.
Last edited by Bunuel on 07 Jul 2016, 21:55, edited 1 time in total.
Renamed the topic and edited the question.
Current Student
Joined: 22 Jun 2016
Posts: 230
Re: Obra drove 160π meters along a circular track. If the area enclosed by  [#permalink]

### Show Tags

07 Jul 2016, 21:39
2
area enclosed by the circular track on which she drove is 57,600π square meters

So, π(r^2) = 57,600π ---> (r^2)=57,600 ---> r=240

Circumference of the circular track = 2πr = 480π

Therefore, part of circumference covered = 160π/480π = 1/3 or 33.33%

----------------------------------------------------

P.S. Don't forget to give kudos
_________________
P.S. Don't forget to give Kudos
Current Student
Joined: 18 Oct 2014
Posts: 803
Location: United States
GMAT 1: 660 Q49 V31
GPA: 3.98
Re: Obra drove 160π meters along a circular track. If the area enclosed by  [#permalink]

### Show Tags

08 Jul 2016, 06:25
EthosGMAT wrote:
Obra drove 160π meters along a circular track. If the area enclosed by the circular track on which she drove is 57,600π square meters, what percentage of the circular track did Obra drive?

A. 6.67%
B. 12.5%
C. 18.75%
D. 25%
E. 33.3%

pi r^2= 57600 pi

r= 240

Total distance= circumference of circle= 2pi r= 480 pi

if 480 pi is 100 %, then 160 pi= 100*160pi/480pi= 33.33% (approximately)

_________________
I welcome critical analysis of my post!! That will help me reach 700+
Intern
Joined: 17 Mar 2016
Posts: 7
Re: Obra drove 160π meters along a circular track. If the area enclosed by  [#permalink]

### Show Tags

08 Jul 2016, 16:26
Thanks for the reply guys! For some reason I thought Obra drove a "part of the circular track" and that 'length of arc' which she drove is 160pi as the question says area enclosed by her on the circular track was sorta confusing wording for me.
Director
Joined: 04 Dec 2015
Posts: 743
Location: India
Concentration: Technology, Strategy
WE: Information Technology (Consulting)
Obra drove 160π meters along a circular track. If the area enclosed by  [#permalink]

### Show Tags

18 Dec 2018, 09:54
EthosGMAT wrote:
Obra drove 160π meters along a circular track. If the area enclosed by the circular track on which she drove is 57,600π square meters, what percentage of the circular track did Obra drive?

A. 6.67%
B. 12.5%
C. 18.75%
D. 25%
E. 33.3%

Area enclosed by circular track; $$\pi r^2 = 57600\pi$$

$$r^2 = 57600$$

$$r = 240$$

Circumference of the Circular track is ; $$2\pi r = 2 \pi * 240 = 480\pi$$

Obra drove $$160\pi$$ of the circumference.

Hence required percentage $$= \frac{160\pi}{480\pi} * 100 = 33.3$$%

Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8086
Location: United States (CA)
Re: Obra drove 160π meters along a circular track. If the area enclosed by  [#permalink]

### Show Tags

28 Jul 2019, 10:14
EthosGMAT wrote:
Obra drove 160π meters along a circular track. If the area enclosed by the circular track on which she drove is 57,600π square meters, what percentage of the circular track did Obra drive?

A. 6.67%
B. 12.5%
C. 18.75%
D. 25%
E. 33.3%

Since the area enclosed by the circular track is 57,600π square meters, the radius of the track, r, can be determined by the equation:

πr^2 = 57,600π

r^2 = 57,600

r = √57,600 = 240

Therefore, the circumference (or length) of the track is 2πr = 2π(240) = 480π meters. So Obra drove

160π/480π = 1/3 or 33.3% of the circular track.

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
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.

Re: Obra drove 160π meters along a circular track. If the area enclosed by   [#permalink] 28 Jul 2019, 10:14
Display posts from previous: Sort by