Returns and Standard Deviations

Consider the following information

		Rate of Return if State Occurs
State of Economy	Probability of State of Economy	Stock A	Stock B	Stock C
Boom	.20	.30	.45	.33
Good	.40	.12	.10	.15
Poor	.30	.01	-.15	-.05
Bust	.10	-.20	-.30	-.09

a) Your portfolio is invested 40 percent each in A and C and 20 percent in B. What is the expected return on the portfolio?

What is the variance of the portfolio? The standard deviation?

Please show your calculations.