Based on the following information, what is the standard dev…

Based on the following information, what is the standard deviation on an equally weighted portfolio of these three stocks?State of Probability of   Rate of Return if State OccursEconomy State of Economy  Stock A Stock B Stock CBoom      0.15                        0.06    0.24       0.24Bust        0.85                      –0.12      –0.30     –0.15