Challenge question: Each edge of the above cube has length 1
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Each edge of the above cube has length 1. If an ant walks from point A to point B along the OUTSIDE of the cube, what is shortest distance the ant must travel?
A) √3
B) 2
C) √5
D) √6
E) √7
Answer: C
Difficulty level: 700+
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*I'll post a full solution in 2 days
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"Open" the cube up, drawing all 6 sides flat. Visualize that the cube's internal surfaces are flat against the table.
So you will have 4 squares in a column, with a square attached to each side of the square one up from the bottom
Points A and B are diagonally across from each other, with the short leg being 1 unit and the long leg being 2 units. Points A and B are on a straight line, therefore the shortest distance.
Apply hypotenuse of right triangle rule: (1^2 + 2^2 )^1/2 = [spoiler]5^1/2, C[/spoiler]
So you will have 4 squares in a column, with a square attached to each side of the square one up from the bottom
Points A and B are diagonally across from each other, with the short leg being 1 unit and the long leg being 2 units. Points A and B are on a straight line, therefore the shortest distance.
Apply hypotenuse of right triangle rule: (1^2 + 2^2 )^1/2 = [spoiler]5^1/2, C[/spoiler]
GMAT/MBA Expert
- Brent@GMATPrepNow
- GMAT Instructor
- Posts: 16207
- Joined: Mon Dec 08, 2008 6:26 pm
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If we open up the cube, we get something like this....Brent@GMATPrepNow wrote:
Each edge of the above cube has length 1. If an ant walks from point A to point B along the OUTSIDE of the cube, what is shortest distance the ant must travel?
A) √3
B) 2
C) √5
D) √6
E) √7
Let x = the distance from A to B
Since we have a right triangle, we can apply the Pythagorean Theorem to get: 1² + 2² = x²
Simplify to get: 1 + 4 = x²
So, 5 = x², which means x = √5
Answer: C
Cheers,
Brent