Special discrete prob. distrib

18(a) P = (0.4)(0.4)(0.6) = 0.096

(b) P = (0.2)(0.2)(0.8) = 0.032

(c) P = [1 - (0.6)(0.8)]^2(0.6)(0.8) = 0.1298

18 (0.7)^n > 0.15 => n = 6

19(a) The probability to get a sliver in each draw = 2/7

So E(n) = 1/(2/7) = 3.5

(b) The probability to get the second coin in each draw = 1/6

E(n) = 6

So, total expected no. = 3.5 + 6 = 9.5