A game of chance offers the following odds and payoffs. Each play of the game costs $100, so the net profit per play is the payoff less $100.

Probability Payoff Net Profit

0.1 $500 $400

0.5 100 0

0.4 0 100

a-1. What is the expected cash payoff? a-2. What is the expected rate of return?

b-1. What is the variance of the expected returns? b-2. What is the standard deviation of the expected returns?