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

 It is currently 23 Jan 2019, 19:04

### 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

## Events & Promotions

###### Events & Promotions in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
• ### Key Strategies to Master GMAT SC

January 26, 2019

January 26, 2019

07:00 AM PST

09:00 AM PST

Attend this webinar to learn how to leverage Meaning and Logic to solve the most challenging Sentence Correction Questions.
• ### Free GMAT Number Properties Webinar

January 27, 2019

January 27, 2019

07:00 AM PST

09:00 AM PST

Attend this webinar to learn a structured approach to solve 700+ Number Properties question in less than 2 minutes.

# Cylinder A, which has a radius of x and a height of y, has a greater

Author Message
Manager
Joined: 24 Jul 2011
Posts: 179
Location: India
GMAT 1: 570 Q50 V19
GMAT 2: 650 Q49 V28
GMAT 3: 690 Q50 V34
WE: Information Technology (Investment Banking)
Cylinder A, which has a radius of x and a height of y, has a greater  [#permalink]

### Show Tags

Updated on: 30 Sep 2015, 23:56
1
00:00

Difficulty:

(N/A)

Question Stats:

50% (02:06) correct 50% (01:26) wrong based on 21 sessions

### HideShow timer Statistics

Geometry MGMAT Question Bank Q24

Cylinder A, which has a radius of x and a height of y, has a greater surface area than does Cylinder B, which has a radius of y and a height of x. How much greater is the surface area of Cylinder A than that of Cylinder of B?

Though options are not available, still it's a good questions.
x/y

_________________

Middle of nowhere!

Originally posted by rohitmanglik on 30 Sep 2015, 22:40.
Last edited by Bunuel on 30 Sep 2015, 23:56, edited 1 time in total.
RENAMED THE TOPIC.
Math Expert
Joined: 02 Aug 2009
Posts: 7213
Re: Cylinder A, which has a radius of x and a height of y, has a greater  [#permalink]

### Show Tags

01 Oct 2015, 18:39
rohitmanglik wrote:
Geometry MGMAT Question Bank Q24

Cylinder A, which has a radius of x and a height of y, has a greater surface area than does Cylinder B, which has a radius of y and a height of x. How much greater is the surface area of Cylinder A than that of Cylinder of B?

Though options are not available, still it's a good questions.
x/y

Hi,
1. Q-- what is the ratio of surface area of cylinder A to cylinder B?..... Ans$$\frac{x}{y}$$
2. for your Q, the answer will $$2pi(x^2-y^2)$$...... How can you have an answer without 2 pi, when both the quantity have 2pi in it...
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

GMAT online Tutor

Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 6834
GMAT 1: 760 Q51 V42
GPA: 3.82
Re: Cylinder A, which has a radius of x and a height of y, has a greater  [#permalink]

### Show Tags

01 Oct 2015, 21:55
Forget conventional ways of solving math questions. In PS, IVY approach is the easiest and quickest way to find the answer.

Cylinder A, which has a radius of x and a height of y, has a greater surface area than does Cylinder B, which has a radius of y and a height of x. How much greater is the surface area of Cylinder A than that of Cylinder of B?

Hi! Well your question is a little bit ambiguous... However, as you mentioned, it is a good question.
So let’s try to get areas of Cylinder A and B.
First of all a Cylinder has two circles(bottom and top) and a rectangle(side) so the area of Cylinder A is 2*pi*x^2 + 2*pi*x*y.
Similarly the area of Cynlinder B is 2*pi*y^2 + 2*pi*x*y.

Since Cylinder A has a greater surface area than does Cylinder B, x > y.
So the difference of area is 2*pi*x^2 + 2*pi*x*y -(2*pi*y^2 + 2*pi*x*y) = 2*pi(x^2 –y^2)
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only \$149 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Intern
Joined: 02 Sep 2017
Posts: 24
Re: Cylinder A, which has a radius of x and a height of y, has a greater  [#permalink]

### Show Tags

30 Mar 2018, 04:27
The surface area of a cylinder = 2 r2 + 2 rh , where r = the radius and h = the height.

Surface area of Cylinder A = 2 x2 + 2 xy

Surface area of Cylinder B = 2 y2 + 2 xy

Surface area of Cylinder A – surface area of Cylinder B =

2 x2 + 2 xy – (2 y2 + 2 xy) = 2 (x2 – y2)
Manager
Status: Studying SC
Joined: 04 Sep 2017
Posts: 120
GPA: 3.6
WE: Sales (Computer Software)
Cylinder A, which has a radius of x and a height of y, has a greater  [#permalink]

### Show Tags

05 Aug 2018, 08:58
Bunuel

Can we just delete or modify this question since it doesn't even have answer choices?

Clearly couldn't be a Manhattan question.
_________________

Would I rather be feared or loved? Easy. Both. I want people to be afraid of how much they love me.

How to sort questions by Topic, Difficulty, and Source:
https://gmatclub.com/forum/search.php?view=search_tags

Cylinder A, which has a radius of x and a height of y, has a greater &nbs [#permalink] 05 Aug 2018, 08:58
Display posts from previous: Sort by