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probability

by g.shankaran » Thu Jun 09, 2011 8:00 am
{ -10, -6, -5, -4, -2.5, -1, 0, 2.5 , 4, 6, 7, 10 }

A number is to be selected at random from the set above. what is the probability that the number selected will be solution of the equation (x-5)(x+10)(2x-5) = 0 ?

1. 1/12
2. 1/6
3. 1/4
4. 1/3
5. 1/2
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by cans » Thu Jun 09, 2011 8:05 am
{ -10, -6, -5, -4, -2.5, -1, 0, 2.5 , 4, 6, 7, 10 }
(x-5)(x+10)(2x-5) = 0
x is either 5 or -10 or 2.5
Total numbers in set = 12
possible options: -10,2.5 = 2
prob = 2/12=1/6
IMO B
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by bubbliiiiiiii » Thu Jun 09, 2011 8:05 am
Solution of equation (x-5)(x+10)(2x-5) = 0 is 5,-10,2.5

Total set consists of 12 elements,
{ -10, -6, -5, -4, -2.5, -1, 0, 2.5 , 4, 6, 7, 10 }

Probability = favourable outcomes/total no. of outcomes

Out of three possible solution of equation only two exists in set.

2c1/12c1 = 2/12 = 1/6

Thus, B
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by jainnikhil02 » Thu Jun 09, 2011 11:57 am
IMO [spoiler]1/6[/spoiler]
Nikhil K Jain
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