Last visit was: 12 Jul 2024, 20:57 It is currently 12 Jul 2024, 20:57
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
SORT BY:
Date
Tags:
Show Tags
Hide Tags
Senior Manager
Senior Manager
Joined: 11 May 2014
Status:I don't stop when I'm Tired,I stop when I'm done
Posts: 473
Own Kudos [?]: 39359 [16]
Given Kudos: 220
Location: Bangladesh
Concentration: Finance, Leadership
GPA: 2.81
WE:Business Development (Real Estate)
Send PM
Manager
Manager
Joined: 28 Jun 2016
Posts: 153
Own Kudos [?]: 192 [0]
Given Kudos: 99
Location: Canada
Concentration: Operations, Entrepreneurship
Send PM
RC & DI Moderator
Joined: 02 Aug 2009
Status:Math and DI Expert
Posts: 11468
Own Kudos [?]: 34263 [2]
Given Kudos: 322
Send PM
Math Expert
Joined: 02 Sep 2009
Posts: 94302
Own Kudos [?]: 640202 [3]
Given Kudos: 84576
Send PM
Re: An insect is located at one corner (point A) on the surface of a cube [#permalink]
2
Kudos
1
Bookmarks
Expert Reply
AbdurRakib wrote:
An insect is located at one corner (point A) on the surface of a cube that measures 3 x 4 x 5 inches, as shown in the diagram.

Note: Figure is not drawn to scale.

If the insect crawls along the surface of the cube to the opposite corner (point B), what is the shortest possible length, in inches, of the insect’s path from point A to point B?

(A)5\(\sqrt{2}\)
(B)\(\sqrt{74}\)
(C)4\(\sqrt{5}\)
(D)3\(\sqrt{10}\)
(E)10


Similar questions to practice:
an-ant-is-clinging-to-one-corner-of-a-box-in-the-shape-of-a-135055.html
s97-184708.html
an-ant-crawls-from-one-corner-of-a-room-to-the-diagonally-134454.html
an-open-empty-rectangular-box-with-negligible-wall-thickness-is-6-feet-197124.html

Hope it helps.
Manager
Manager
Joined: 21 Aug 2016
Posts: 222
Own Kudos [?]: 153 [0]
Given Kudos: 145
Location: India
GPA: 3.9
WE:Information Technology (Computer Software)
Send PM
An insect is located at one corner (point A) on the surface of a cube [#permalink]
chetan2u wrote:
AbdurRakib wrote:
An insect is located at one corner (point A) on the surface of a cube that measures 3 x 4 x 5 inches, as shown in the diagram.

Note: Figure is not drawn to scale.

If the insect crawls along the surface of the cube to the opposite corner (point B), what is the shortest possible length, in inches, of the insect’s path from point A to point B?

(A)5\(\sqrt{2}\)
(B)\(\sqrt{74}\)
(C)4\(\sqrt{5}\)
(D)3\(\sqrt{10}\)
(E)10


Hi

Two points..
1) A cube is supposed to have same dimensions so it will be 3*3*3 or 4*4*4... here it is cuboid..
2) Now the answer..
a) if it can fly and is inside the box, it will be DIAGONAL.
b) but here it is crawling, so open the two rectangle faces adjacent.. these faces are 3*5 and 4*5..
So when you open it, it becomes rectangle with sides 3+4 and 5..
So the hypotenuse of this triangle will be our ANSWER and it is √(7^2+5^2)=√(49+25)=√74


Hi chetan2u,

As it is a cuboid, I tried to solve in below way, but it is incorrect

first sqrt(3^2+4^2)=sqrt(9+16)=5 --- find the diagonal that will work the edge for second triangle
then diagonal it needs to travel = sqrt(25+25)=5*sqrt(2)

However, if we solve in the following way, it is correct

sqrt((3+4)^2 +5^2)

Why is first approach incorrect?
Retired Moderator
Joined: 22 Aug 2013
Posts: 1181
Own Kudos [?]: 2548 [2]
Given Kudos: 459
Location: India
Send PM
Re: An insect is located at one corner (point A) on the surface of a cube [#permalink]
2
Kudos
As attached in the picture..

Questions like these are best done by opening up the cube/cuboid (which makes a rectangle), and then applying pythagoras theorem.

Shortest path for the insect will pass from A, to somewhere along the left edge of the given cuboid, and then to B.

Or we could also go from point A to somewhere along right edge of given cuboid, and then to B. Answer will be same.

Hence B answer
Attachments

IMG_20170622_155621.jpg
IMG_20170622_155621.jpg [ 50.67 KiB | Viewed 15743 times ]

RC & DI Moderator
Joined: 02 Aug 2009
Status:Math and DI Expert
Posts: 11468
Own Kudos [?]: 34263 [1]
Given Kudos: 322
Send PM
An insect is located at one corner (point A) on the surface of a cube [#permalink]
1
Kudos
Expert Reply
AR15J wrote:
chetan2u wrote:
AbdurRakib wrote:
An insect is located at one corner (point A) on the surface of a cube that measures 3 x 4 x 5 inches, as shown in the diagram.

Note: Figure is not drawn to scale.

If the insect crawls along the surface of the cube to the opposite corner (point B), what is the shortest possible length, in inches, of the insect’s path from point A to point B?

(A)5\(\sqrt{2}\)
(B)\(\sqrt{74}\)
(C)4\(\sqrt{5}\)
(D)3\(\sqrt{10}\)
(E)10


Hi

Two points..
1) A cube is supposed to have same dimensions so it will be 3*3*3 or 4*4*4... here it is cuboid..
2) answer as mentioned above will be 10...
It has to travel on diagonal of rectangle of size 3*4 and then along length/edge of size 5..



Hi chetan2u,

As it is a cuboid, I tried to solve in below way, but it is incorrect

first sqrt(3^2+4^2)=sqrt(9+16)=5 --- find the diagonal that will work the edge for second triangle
then diagonal it needs to travel = sqrt(25+25)=5*sqrt(2)

However, if we solve in the following way, it is correct

sqrt((3+4)^2 +5^2)

Why is first approach incorrect?



Hi..
In first case after you take √(3^2+4^2)=5, you get a diagonal of the BASE of the given cuboid.
By taking the √(5^2+5^2), you are finding the DIAGONAL of the cuboid and this would be correct if the insect is flying BUT the insect is moving along the surface.
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 33955
Own Kudos [?]: 851 [0]
Given Kudos: 0
Send PM
Re: An insect is located at one corner (point A) on the surface of a cube [#permalink]
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.
GMAT Club Bot
Re: An insect is located at one corner (point A) on the surface of a cube [#permalink]
Moderator:
Math Expert
94302 posts