Happy National Bank is thinking about adding a new branch in a very different area. They estimate that the new office will have an expected return of 16% with a standard deviation of 8%. Currently they have an expected return of 12% with a standard deviation of 4%. The correlation between the new branch will represent 15% of the revenuers of the bank in 20 years. What is the bank's expected risk (measured by the standard deviation) with the new branch? Round to the nearest .1 percent. Please show step by step calculations.