If one invested in Stock A, what would be the standard deviation of the percentage...

The annual returns, in percentages, on stocks A and B for three possible states of the economy are given in the table below.

Economy State       |   Probability    |   StockA     |   StockB
Good                0.5          40          20
Average                0.3          20          40
Bad                   0.2          10          8

If one invested in StockA, what would be the standard deviation of the percentage return? Place your answer, in
percent rounded to 1 decimal place, in the blank. For example, a standard deviation of 10.39 percent would be
reported as 10.4. Do not use a percent sign.