Find the expected payback for the games of chance described in Exercises 47–52.
Keno In one form of the game Keno, the house has a pot containing 80 balls, each marked with a different number from 1 to 80. You buy a ticket for $\$ 1$ and mark one of the 80 numbers on it. The house then selects 20 numbers at random. If your number is among the $20,$ you get $\$ 3.20$ (for a net winning of $\$ 2.20$ )