NEW HERE? LEARN MORE
closeclose
Last visit was: 24 Apr 2024, 02:56 It is currently 24 Apr 2024, 02:56
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

The length of a rope, by which a cow is tied, is decreased from 22m

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
P
Gnpth
VP
VP
Joined: 29 Aug 2012
Status:Chasing my MBB Dream!
Posts: 1057
Own Kudos [?]: 6254 [1]
Given Kudos: 330
Location: United States (DC)
WE:General Management (Aerospace and Defense)
Send PM
GMAT ToolKit User Reviews Badge
The length of a rope, by which a cow is tied, is decreased from 22m [#permalink] New post   19 Aug 2015, 02:44
1
Bookmarks
00:00
A
B
C
D
E

Difficulty:

15% (low)

Question Stats:

80% (01:23) correct 20% (01:59) wrong based on 40 sessions
Hide Show timer Statistics
The length of a rope, by which a cow is tied, is decreased from 22m to 14m. What is the decrease in the area that can be grazed by the cow?

(A) \(288\pi\)

(B) \(144\pi\)

(C) \(200\pi\)

(D) \(120\pi\)

(E) \(72\pi\)

Source : Aristotle Prep
ShowHide Answer
Official Answer
A
avatar
B
AmoyV
Retired Moderator
Joined: 30 Jul 2013
Status:On a mountain of skulls, in the castle of pain, I sit on a throne of blood.
Posts: 261
Own Kudos [?]: 655 [0]
Given Kudos: 134
Send PM
GMAT ToolKit User Reviews Badge
The length of a rope, by which a cow is tied, is decreased from 22m [#permalink] New post   16 Feb 2016, 02:08
Length of the rope is the radius of the circle.

Decrease in the area grazed by the cow = \(\pi\) (\(22^2\) - \(14^2\))
= (22-14)(22+14)\(\pi\)
= 8(36)\(\pi\)
=288\(\pi\)

Answer: A
User avatar
S
garcmillan
Manager
Manager
Joined: 24 Sep 2015
Posts: 71
Own Kudos [?]: 77 [0]
Given Kudos: 79
Location: Spain
Concentration: Strategy, Entrepreneurship
GPA: 3.9
WE:Management Consulting (Consulting)
Send PM
The length of a rope, by which a cow is tied, is decreased from 22m [#permalink] New post   18 Aug 2019, 06:53
One of the errors that GMAT exam makers want you to make here is confusing radius and diameter

Don't divide the 22m and 14m by two and use that resulting number as the radius because the whole length of the rope is already the radius!

1º Area (22m): 22^2 * pi = 484 * pi
2º Area (14m): 14^2 * pi = 196 * pi

Differences: 484 * pi - 196 * pi = 288 * pi

OPTION A
User avatar
L
Abhishek009
Board of Directors
Joined: 11 Jun 2011
Status:QA & VA Forum Moderator
Posts: 6072
Own Kudos [?]: 4689 [0]
Given Kudos: 463
Location: India
GPA: 3.5
WE:Business Development (Commercial Banking)
Send PM
GMAT ToolKit User
Re: The length of a rope, by which a cow is tied, is decreased from 22m [#permalink] New post   18 Aug 2019, 07:18
Gnpth wrote:
The length of a rope, by which a cow is tied, is decreased from 22m to 14m. What is the decrease in the area that can be grazed by the cow?

(A) \(288\pi\)

(B) \(144\pi\)

(C) \(200\pi\)

(D) \(120\pi\)

(E) \(72\pi\)

Source : Aristotle Prep


π(R^2 - r^2)

= π(R + r)(R - r)

= π (22+14)(22 - 14)

= π*36*8

= 288π, Answer must be (A)
User avatar
L
Kinshook
GMAT Club Legend
GMAT Club Legend
Joined: 03 Jun 2019
Posts: 5342
Own Kudos [?]: 3964 [0]
Given Kudos: 160
Location: India
Schools: HBS '22 CBS '22 Wharton '22
GMAT 1: 690 Q50 V34
WE:Engineering (Transportation)
Send PM
Reviews Badge
The length of a rope, by which a cow is tied, is decreased from 22m [#permalink] New post   18 Aug 2019, 07:44
Gnpth wrote:
The length of a rope, by which a cow is tied, is decreased from 22m to 14m. What is the decrease in the area that can be grazed by the cow?

(A) \(288\pi\)

(B) \(144\pi\)

(C) \(200\pi\)

(D) \(120\pi\)

(E) \(72\pi\)

Source : Aristotle Prep


Given: The length of a rope, by which a cow is tied, is decreased from 22m to 14m.

Asked: What is the decrease in the area that can be grazed by the cow?

The decrease in the area that can be grazed by the cow \(= \pi 22^2 - \pi 14^2 = \pi (22^2 - 14^2) = \pi (22+14)(22-14) = \pi 36*8 = 288 \pi\)

IMO A
GMAT Club Bot
gmatclubot
The length of a rope, by which a cow is tied, is decreased from 22m [#permalink]
18 Aug 2019, 07:44
Moderators:
Bunuel
Math Expert
92901 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions