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Old 2009 January 3rd, 08:46 AM   #1 (permalink)
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Probability question, please help

Given numbers from 1 to 10. Two numbers are to be selected from these 10 numbers and they can be same also. What is the probability that at least one of them is even?
A. 1/2
B. 3/4
C. 1/4
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Old 2009 January 4th, 04:33 AM   #2 (permalink)
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odd->1,3,5,7,9
p(odd) = 5/10
=1/2
even->2,4,6,8,10
p(even) = 5/10
=1/2

p(atleast 1 is even) = 1 -p(none of them are even)
= 1- 1/2*1/2
= 1 -1/4
= 3/4

I am taking that this problem is with replacement since it says the numbers can be the same also.
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Old 2009 January 4th, 09:30 AM   #3 (permalink)
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Thanks Cramya, but I still did not understand

p(atleast 1 is even) = 1 -p(none of them are even)
= 1- 1/2*1/2
= 1 -1/4
= 3/4
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