9709 P53 - Nov 2020 - Q2
3100
An ordinary fair die is thrown until a 6 is obtained.
(a) Find the probability that obtaining a 6 takes more than 8 throws.
Two ordinary fair dice are thrown together until a pair of 6s is obtained. The number of throws taken is denoted by the random variable X.
(b) Find the expected value of X.
(c) Find the probability that obtaining a pair of 6s takes either 10 or 11 throws.
