Tom is managing a $$20$ million portfolio that has a beta of $1\mathrm{.}5$ and a required rate of return of $13\mathrm{.}6\%.$ The current risk$-$free rate is $3\mathrm{.}4\%.$ Assume that Tom receives another $$5$ million. If Tom invests the money in a stock with a beta of $0\mathrm{.}63,$ what will be the required return on Tom$$s $25$ million portfolio?

$($Hint: find the market risk premium $($rM $$ rRF$)$ first using the information of the original portfolio, next find the new portfolio beta and then the required rate of return$).$