A Level Appplied Maths

14 (a) In the first round A has 2^3 - 1 = 7 possible adversaries, of whom one is B. So the probability that he will play B in the first round is 1/7.

(b) Since there are 2^3 - 1 = 7 actual pairings against a possible C(2^3, 2) = 28 pairings, the chance that any two people meet is 7/28=1/4 So the probability that A and B will not meet is 1-1/4=3/4

2010-05-29 16:58:57 補充：
The answer should be 1/4 since the meaning of ever is "meet"

2/8 and 4/8?