A game in a casino has four possible outcomes: green, red, white, and blue. The probability of green occurring is 1 /8 . The probability of red occurring is 1 /8 . The probability of white occurring is 1/ 4 . The probability of blue occurring is 1 /2 . Assume that outcomes of each play of this game are independent.

a. What is the expected number of plays required for green to occur once?

b. What is the expected number of plays required for green to occur twice?

c. What is the expected number of plays required until at least one green and one red have occurred?

d. What is the expected number of plays required until at least two greens and one red have occurred?

e. What is the expected number of plays required for green to occur two times in a row?