Question 872016
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Hi
9Balls: 4B, 5W
Assume that the first ball is returned before the second ball is drawn.
a) 2draws:  P(2W) = {{{(5/9)(4/9)}}}
b) 2 consecutive draws(w/o replacement):  P(B and W) = {{{(4/9)(5/8)}}}
c) 4 consecutive draws(w/o replacement): P(at least 1 B) = 1- P(no B) = 1- {{{(5/9)(4/8)(3/7)(2/6) }}}