SOLUTION: Two game tiles, numbered 1 through 9, are selected at random from a box without replacement. If their sum is even, what is the probability that both numbers are odd?

Question 1172383: Two game tiles, numbered 1 through 9, are selected at random from a box without replacement. If their sum is even, what is the probability that both numbers are odd?
Answer by ikleyn(52788) (Show Source): You can put this solution on YOUR website!
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If their sum is even, it means that EITHER both numbers are odd OR both numbers are even.


Among the numbers 1 to 9 inclusive, there are 5 odd and 4 even numbers.


So,  P(the sum is even) = P(both are odd) + P(both are even) =  =  = .    


From the other hand side,  P(both are odd) =  = .


Therefore, the conditional probability that both numbers are odd, given that their sum is even, is equal to


    P(final) =  =  =  = .    ANSWER

Solved.

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