Question

The author purchased a slot machine configured so that there is a 1/2000 probability of winning the jackpot on any individual trial. Although no one would seriously consider tricking the author, suppose that a guest claims that she played the slot machine 5 times and hit the jackpot twice.

Find the probability of at least 2 jackpots in 5 trials

Answer 1

C(5,2) = 5!/[3!(2!)] = 5*4 /2 = 10

P(2 in 5 trials) = 10 (1/2000)^2 (1-1/2000)^3

(1-1/2000)^3 is about 1
so
10/(2 *10*3)^2 = (10/4)* 10^-6
= 2.5 * 10^-6 = 0.0000025

Answer 2

Thank you...