|
Answer» 49%
Let A be the EVENT that a boy wins 1ST ROUND Let B be the event that a girl wins 2nd round. Then, A' = Event that the boy losses 1st round and B' = event that the girl losses 2nd round. Therefore, P(A) = 55/100 = 11/20, P(B) = 60/100 = 12/20. P(A') = 1- (11/20) = 9/20 and P(B') = 1- (12/20) = 8/20 First, we have to find the probability that they contradict each other; That is, P( A And B contradicts each other) = P[(boy WIN in 1st round And girl losses in 2nd round) (Or) (boy losses in 1st round And girl wins in 2nd round) = P[(A And B') Or (A' And B)] = P[(A And B')] + p[(A' And B)] = P(A) x P(B') + P(A') x P(B) = 11/20 x 8/20 + 9/20 x 12/20 = 88/400 + 108/400 = 196/400 We have to find the %. Required % = (196/400)x100 = 49%.
|