You invested $$2,500$ in a portfolio with an expected return of $10$ percent and $$3,500$ in a portfolio with an expected return of $15$ percent. What is the expected return of the combined portfolio?

$12\mathrm{.}9\%$

$13\mathrm{.}6\%$

$6\mathrm{.}1\%$

$12\mathrm{.}0\%$