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tricky question - probability

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tricky question - probability

by agganitk » Sun Oct 11, 2009 1:43 am
A 5 meter long wire is cut into two pieces. If the longer piece is then used to form a perimeter of a square, what is the probability that the area of the square will be more than 1 if the original wire was cut at an arbitrary point?

1/4
3/10
2/5
5/12
1/2

[spoiler] 2/5 :shock: [/spoiler]
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Is the answer

by enniguy » Sun Oct 11, 2009 5:22 am
Is the answer C - 2/5?

For the area of the sqaure to be "atleast" 1, a^2 should be atleast 1. This can happen only when the sides of the sqaure is atleast 1.

This means, the perimeter of the square is 4. Now, there is 2 points at which you can cut the wire to get 4 length.

Consider this your wire:
0----1-----2-----3-----4-----5

You can cut at 1 OR 4. Then you will have wires (1,4) or (4,1).

Hence, it is 2/5.
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by agganitk » Sun Oct 11, 2009 5:34 am
yes your ans is 100 % correct
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