You put $70\%$ of your money in a stock portfolio that has an expected return of $12\mathrm{.}5\%$ and a standard deviation of $28\%.$ You put the rest of your money in a risky bond portfolio that has an expected return of $3\mathrm{.}5\%$ and a standard deviation of $15\%.$ The stock and bond portfolio have a correlation $0\mathrm{.}25.$ What is the standard deviation of the resulting portfolio? Do not enter $\%$ in the answer box. For example, if your answer is $0\mathrm{.}12345$ or $12\mathrm{.}345\%$ then enter as $12\mathrm{.}35$ in the answer box.