It is currently 20 Jan 2018, 10:48

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

The figure above represents a right circular cylindrical tube made out

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Expert Post
1 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43335

Kudos [?]: 139576 [1], given: 12794

The figure above represents a right circular cylindrical tube made out [#permalink]

Show Tags

New post 08 Dec 2017, 02:46
1
This post received
KUDOS
Expert's post
2
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

32% (01:06) correct 68% (05:26) wrong based on 56 sessions

HideShow timer Statistics

Image
The figure above represents a right circular cylindrical tube made out of paper. The circumference of each circular base is 10 centimeters, the length of AB is 12 centimeters, and BD is a diameter of a base. If the tube is cut along AB, opened and flattened, what is the length of AD in centimeters?

(A) 13
(B) 17
(C) 22
(D) 2√61
(E) √146.5

[Reveal] Spoiler:
Attachment:
2017-12-08_1440_002.png
2017-12-08_1440_002.png [ 6.2 KiB | Viewed 661 times ]
[Reveal] Spoiler: OA

_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 139576 [1], given: 12794

Director
Director
User avatar
P
Joined: 18 Aug 2016
Posts: 627

Kudos [?]: 208 [0], given: 167

Concentration: Strategy, Technology
GMAT 1: 630 Q47 V29
GMAT 2: 740 Q51 V38
GMAT ToolKit User Premium Member Reviews Badge
Re: The figure above represents a right circular cylindrical tube made out [#permalink]

Show Tags

New post 08 Dec 2017, 03:01
Bunuel wrote:
Image
The figure above represents a right circular cylindrical tube made out of paper. The circumference of each circular base is 10 centimeters, the length of AB is 12 centimeters, and BD is a diameter of a base. If the tube is cut along AB, opened and flattened, what is the length of AD in centimeters?

(A) 13
(B) 17
(C) 22
(D) 2√61
(E) √146.5

[Reveal] Spoiler:
Attachment:
2017-12-08_1440_002.png


Radius = >
2*pie * r = 10
r = 5/pie
ABD will be right angle Triangle
AD is Hypotenuse and hence can be calculated
AD = \(\sqrt{(12^2 + (5/pie)^2)}\)
AD = \(\sqrt{(144 + 25/~9.5)} = \sqrt{146.5}\)
E
_________________

We must try to achieve the best within us


Thanks
Luckisnoexcuse

Kudos [?]: 208 [0], given: 167

1 KUDOS received
Manager
Manager
avatar
B
Joined: 24 Nov 2016
Posts: 151

Kudos [?]: 31 [1], given: 40

Re: The figure above represents a right circular cylindrical tube made out [#permalink]

Show Tags

New post 08 Dec 2017, 05:44
1
This post received
KUDOS
Bunuel wrote:
Image
The figure above represents a right circular cylindrical tube made out of paper. The circumference of each circular base is 10 centimeters, the length of AB is 12 centimeters, and BD is a diameter of a base. If the tube is cut along AB, opened and flattened, what is the length of AD in centimeters?

(A) 13
(B) 17
(C) 22
(D) 2√61
(E) √146.5

[Reveal] Spoiler:
Attachment:
2017-12-08_1440_002.png


If the tube is opened and flattened, then we have a rectangle with length 12 = AB, and width 10 = the circumference.

Now, lines BD and AC are equal to half the width = 10/2 = 5.

So to find the distance AD, we need to find the diagonal of the rectangle with length 12 = AB and width 5 = BD

\(a^2+b^2=c^2, 12^2+5^2=c^2, 169=c^2, c=13\)

(A) is the answer.

Last edited by exc4libur on 09 Dec 2017, 08:06, edited 1 time in total.

Kudos [?]: 31 [1], given: 40

Expert Post
2 KUDOS received
Veritas Prep GMAT Instructor
User avatar
G
Joined: 16 Oct 2010
Posts: 7868

Kudos [?]: 18488 [2], given: 237

Location: Pune, India
Re: The figure above represents a right circular cylindrical tube made out [#permalink]

Show Tags

New post 08 Dec 2017, 06:15
2
This post received
KUDOS
Expert's post
Bunuel wrote:
Image
The figure above represents a right circular cylindrical tube made out of paper. The circumference of each circular base is 10 centimeters, the length of AB is 12 centimeters, and BD is a diameter of a base. If the tube is cut along AB, opened and flattened, what is the length of AD in centimeters?

(A) 13
(B) 17
(C) 22
(D) 2√61
(E) √146.5

[Reveal] Spoiler:
Attachment:
2017-12-08_1440_002.png


When you cut along AB and open it, you get a rectangle. Notice that in this rectangle, A is on the corner and D is in the centre of the opposite edge. So ABD will form a right triangle.

AB^2 + BD^2 = AD^2

AB is simply the length of the tube at 12 cm but notice what BD is. It is half the circumference of the circular base (since it is opened and flattened) which is 10 cm. So BD = 10/2 = 5 cm

This will be a 5-12-13 triangle then and AD will be 13 cm.

Answer (A)
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Kudos [?]: 18488 [2], given: 237

Expert Post
1 KUDOS received
Veritas Prep GMAT Instructor
User avatar
G
Joined: 16 Oct 2010
Posts: 7868

Kudos [?]: 18488 [1], given: 237

Location: Pune, India
Re: The figure above represents a right circular cylindrical tube made out [#permalink]

Show Tags

New post 08 Dec 2017, 20:15
1
This post received
KUDOS
Expert's post
VeritasPrepKarishma wrote:
Bunuel wrote:
Image
The figure above represents a right circular cylindrical tube made out of paper. The circumference of each circular base is 10 centimeters, the length of AB is 12 centimeters, and BD is a diameter of a base. If the tube is cut along AB, opened and flattened, what is the length of AD in centimeters?

(A) 13
(B) 17
(C) 22
(D) 2√61
(E) √146.5

[Reveal] Spoiler:
Attachment:
The attachment 2017-12-08_1440_002.png is no longer available


When you cut along AB and open it, you get a rectangle. Notice that in this rectangle, A is on the corner and D is in the centre of the opposite edge. So ABD will form a right triangle.

AB^2 + BD^2 = AD^2

AB is simply the length of the tube at 12 cm but notice what BD is. It is half the circumference of the circular base (since it is opened and flattened) which is 10 cm. So BD = 10/2 = 5 cm

This will be a 5-12-13 triangle then and AD will be 13 cm.

Answer (A)


Responding to a pm:

Quote:
Can you help me understand how BD is half the circumference of the circular base. I am unable to visualize and hence not getting the point.


Here is the original roll.

Attachment:
Rectangular Roll Original.jpg
Rectangular Roll Original.jpg [ 11.96 KiB | Viewed 395 times ]


When you open it, this is what it looks like.

Attachment:
Rectangular Roll.jpg
Rectangular Roll.jpg [ 14.09 KiB | Viewed 395 times ]

_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Kudos [?]: 18488 [1], given: 237

1 KUDOS received
Intern
Intern
avatar
B
Joined: 19 Aug 2017
Posts: 20

Kudos [?]: 1 [1], given: 215

CAT Tests
Re: The figure above represents a right circular cylindrical tube made out [#permalink]

Show Tags

New post 22 Dec 2017, 05:48
1
This post received
KUDOS
Got the answer to be A :|

Can anyone explain how it is D??

Kudos [?]: 1 [1], given: 215

Expert Post
1 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43335

Kudos [?]: 139576 [1], given: 12794

Re: The figure above represents a right circular cylindrical tube made out [#permalink]

Show Tags

New post 22 Dec 2017, 05:57
1
This post received
KUDOS
Expert's post

Kudos [?]: 139576 [1], given: 12794

Intern
Intern
avatar
B
Joined: 19 Aug 2017
Posts: 20

Kudos [?]: 1 [0], given: 215

CAT Tests
Re: The figure above represents a right circular cylindrical tube made out [#permalink]

Show Tags

New post 22 Dec 2017, 06:06
Bunuel wrote:
MSarmah wrote:
Got the answer to be A :|

Can anyone explain how it is D??


The correct answer is A. Edited. Thank you.



Welcome Brunnel :-)

Kudos [?]: 1 [0], given: 215

Re: The figure above represents a right circular cylindrical tube made out   [#permalink] 22 Dec 2017, 06:06
Display posts from previous: Sort by

The figure above represents a right circular cylindrical tube made out

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.