Question: SLOT MACHINES A "lucky dollar" is one of the nine symbols printed on each reel of a slot machine with three reels. A player receives one of various payouts whenever one or more "lucky dollars" appear in the window of the machine. Find the number of winning combinations for which the machine gives a payoff.
Hint: (a) Compute the number of ways in which the nine symbols on the first, second, and third wheels can appear in the window slot and
(b) compute the number of ways in which the eight symbols other than the "lucky dollar" can appear in the window slot. The difference (a - b) is the number of ways in which the "lucky dollar" can appear in the window slot. Why?