Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 13 Dec 2013, 01:48

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# At a certain pizza parlor, the diameter of a large pizza is

Author Message
TAGS:
Magoosh GMAT Instructor
Joined: 28 Dec 2011
Posts: 1345
Followers: 327

Kudos [?]: 1159 [1] , given: 20

At a certain pizza parlor, the diameter of a large pizza is [#permalink]  10 Oct 2012, 10:04
1
KUDOS
Expert's post
00:00

Difficulty:

35% (medium)

Question Stats:

70% (19:59) correct 29% (01:19) wrong based on 72 sessions
At a certain pizza parlor, the diameter of a large pizza is 40% larger than the diameter of a small pizza. What is the percent increase in total amount of pizza, from a small to a large?

(A) 20%
(B) 40%
(C) 64%
(D) 80%
(E) 96%

See a full discussion of the mathematical principles involved in this question, as well as a complete solution, at:
http://magoosh.com/gmat/2012/scale-fact ... decreases/
[Reveal] Spoiler: OA

_________________

Mike McGarry
Magoosh Test Prep

 Kaplan GMAT Prep Discount Codes Knewton GMAT Discount Codes Veritas Prep GMAT Discount Codes
Senior Manager
Joined: 28 Jun 2009
Posts: 455
Location: United States (MA)
Followers: 14

Kudos [?]: 93 [1] , given: 46

Re: At a certain pizza parlor, the diameter [#permalink]  10 Oct 2012, 10:18
1
KUDOS
Let the pizzas be thin crust! Not considering height.

Small : diameter x, radius x/2, area (total amount of pizza) = pi * (x/2)^2
Large : diameter 1.4x, radius 1.4x/2, area (total amount of pizza) = pi * (1.4x/2)^2 = (1.4)^2 * area of small pizza = 1.96 * area of small pizza

So E is right.
Math Expert
Joined: 02 Sep 2009
Posts: 15143
Followers: 2536

Kudos [?]: 15641 [1] , given: 1565

Re: At a certain pizza parlor, the diameter [#permalink]  10 Oct 2012, 10:38
1
KUDOS
Expert's post
mikemcgarry wrote:
At a certain pizza parlor, the diameter of a large pizza is 40% larger than the diameter of a small pizza. What is the percent increase in total amount of pizza, from a small to a large?
(A) 20%
(B) 40%
(C) 64%
(D) 80%
(E) 96%

See a full discussion of the mathematical principles involved in this question, as well as a complete solution, at:
http://magoosh.com/gmat/2012/scale-fact ... decreases/

We need to find by what percent is the area of big pizza greater than the area of small pizza.

Since D (diameter) in the area formula is squared (area=\frac{\pi*d^2}{4}), then 40% increase in diameter, or increase 1.4 times, would be equivalent to 1.4^2=1.96 times increase in the area, which is the same as 96% increase.

_________________
Director
Joined: 09 Sep 2013
Posts: 594
Followers: 71

Kudos [?]: 10 [0], given: 0

Re: At a certain pizza parlor, the diameter [#permalink]  23 Nov 2013, 01:01
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.
_________________
Re: At a certain pizza parlor, the diameter   [#permalink] 23 Nov 2013, 01:01
Similar topics Replies Last post
Similar
Topics:
At certain pizzeria 1/8 of the pizzas sold in one week were 3 15 May 2006, 03:05
DS - Pizza 6 13 Dec 2006, 10:06
1) At Joe's Pizza Parlor, in addition to cheese there are 8 6 13 Feb 2007, 02:59
At a Pizza Parlor, in addition to cheese there are 10 5 23 Jun 2007, 05:05
Marty's Pizza Shop guarantees that their pizzas all have a 3 27 Feb 2013, 03:14
Display posts from previous: Sort by