Both assets A and B plot on the SML$.$ Asset A has an expected return of $18\%$ and a beta of $1\mathrm{.}8.$ Asset B has an expected return of $15\%$ and a beta of $1\mathrm{.}4.$ What is the expected return on the market portfolio? $($Hint: first, find the market risk premium, then find the risk$-$free rate, and finally the market portfolio return$)$