Last visit was: 13 Dec 2024, 14:50 It is currently 13 Dec 2024, 14:50
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
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 13 Dec 2024
Posts: 97,874
Own Kudos:
685,614
 []
Given Kudos: 88,269
Products:
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 97,874
Kudos: 685,614
 []
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
User avatar
Skywalker18
User avatar
Retired Moderator
Joined: 08 Dec 2013
Last visit: 15 Nov 2023
Posts: 2,079
Own Kudos:
9,309
 []
Given Kudos: 171
Status:Greatness begins beyond your comfort zone
Location: India
Concentration: General Management, Strategy
GPA: 3.2
WE:Information Technology (Consulting)
Products:
Posts: 2,079
Kudos: 9,309
 []
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
avatar
sameerspice
Joined: 16 Apr 2015
Last visit: 31 Jul 2020
Posts: 24
Own Kudos:
125
 []
Given Kudos: 132
Posts: 24
Kudos: 125
 []
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
happy1992
Joined: 17 Apr 2016
Last visit: 20 May 2016
Posts: 19
Own Kudos:
Given Kudos: 16
Posts: 19
Kudos: 315
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi, Guyes I have found this problem from a website but I couldn't find the explanation of this problem. Please help me if anybody is there.
User avatar
Abhishek009
User avatar
Board of Directors
Joined: 11 Jun 2011
Last visit: 02 Oct 2024
Posts: 6,014
Own Kudos:
Given Kudos: 463
Status:QA & VA Forum Moderator
Location: India
GPA: 3.5
WE:Business Development (Commercial Banking)
Posts: 6,014
Kudos: 4,952
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
The length of a rope, to which a cow is tied, is increased from 19 m to 30 m. How much additional ground will it be able to graze? Assume that the cow is able to move on all sides with equal ease. Use \(\pi = \frac{22}{7}\) in your calculations.

A. 1594 sq m
B. 1694 sq m
C. 1696 sq m
D. 1756 sq.m
E. 1896 sq.m

Attachment:
Circle.PNG
Circle.PNG [ 13.42 KiB | Viewed 14733 times ]

Area of the shaded region is

\(\frac{22}{7}(R^2 - r^2)\) R = 30 and r = 19

So, \(\frac{22}{7}(30^2 -19^2)\)

Or, \(\frac{22}{7}(30 - 19)(30 + 19)\)

Or, \(\frac{22}{7}*11*49\) = 1694

Hence IMHO (B) 1694 :-D
User avatar
chetan2u
User avatar
RC & DI Moderator
Joined: 02 Aug 2009
Last visit: 12 Dec 2024
Posts: 11,434
Own Kudos:
Given Kudos: 333
Status:Math and DI Expert
Products:
Expert reply
Posts: 11,434
Kudos: 38,023
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
The length of a rope, to which a cow is tied, is increased from 19 m to 30 m. How much additional ground will it be able to graze? Assume that the cow is able to move on all sides with equal ease. Use \(\pi = \frac{22}{7}\) in your calculations.

A. 1594 sq m
B. 1694 sq m
C. 1696 sq m
D. 1756 sq.m
E. 1896 sq.m

Hi,

All though the exact method has been given above, ONE easy way to exploit the number properties..

The area will be a multiple of 11 and there is no fraction to cancel out this 11..
so our answer should be a MULTIPLE of 11...

ONLY B is a multiple of 11...

Property of a number to be div by 11:-
the difference in the SUM of alternate digits, that is, SUM of ODD digits- SUM of EVEN digits should be a multiple of 11 including 0...

1694... 4+6-(1+9)=0..
B
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 35,810
Own Kudos:
Posts: 35,810
Kudos: 929
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Moderator:
Math Expert
97874 posts