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Probability ( Really difficult)

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Probability ( Really difficult)

by akpareek » Fri Jul 30, 2010 5:21 am
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}
If an integer is to be randomly selected from set M above and an integer is to be
randomly selected from set T above, what is the probability that the product of the two
integers will be negative?
A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5
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by kmittal82 » Fri Jul 30, 2010 5:37 am
Any number selected from set M multiplied by any positive number from set T will give you a negative result.

Probability of selecting a -ve number from set M = 1 (all numbers are negative)
Probability of selecting a +ve number from set T = 3/6 = 1/2

Thus, total probability = 1x1/2 = 1/2

Should be (D). Can you pls confirm thats the OA?
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by akpareek » Fri Jul 30, 2010 6:07 am
kmittal82 wrote:Any number selected from set M multiplied by any positive number from set T will give you a negative result.

Probability of selecting a -ve number from set M = 1 (all numbers are negative)
Probability of selecting a +ve number from set T = 3/6 = 1/2

Thus, total probability = 1x1/2 = 1/2

Should be (D). Can you pls confirm thats the OA?

Its Absolutely rite... thanks
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by indiantiger » Sun Aug 01, 2010 2:27 pm
first set has all negative numbers and total 5 numbers
second set has 2 negative , one zero and 3 positive numbers

for a numbers product to be negative we need one of the multiple to be negative so first can only generate negative numbers by multiplying with 3 positive numbers in set second

total negative products = 15

total products possible between first set and second = 30

probability = 15/30 = 1/2
"Single Malt is better than Blended"
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