13. If a triangle is chosen at random, then what is the probability that the orthocentre lies inside the circumcircle of the triangle.
1. A bag contains "W" white and 3 black balls. Balls are drawn one by one without
replacement till all the black balls are drawn. What is the probability that this
procedure for drawing the balls will come to an end at the r th draw
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5 Answers
12. '2n' players S1, S2.........S2n play in a tournament. They are divided into n pairs at random. From each pair a winner is decided onthe
basis of a game played between the two players of the pair. Assume that all the
players are of equal strength
(a) find the probability that the player S1 is among the eight winner
(b) find the probability that exactly one of the two players S1 and S2 is among the 'n' winner.
(c) It is found that S4 is among the 'n' winners and S1 is not among this 'n' winners. Find the probability that S1 and S4were
in the same pair.
1
1Please post the solution.
No utd4ever, ans given is 3(r-1)(r-2)/[(W+3)(W+2)(W+1)]