John Smith has $$120,000$ invested in a $2-$stock portfolio. $$80,000$ is invested in Stock X and the remainder is invested in Stock Y$.$ Stock X has a beta of $1\mathrm{.}5$ and the portfolio has a beta equal to that of the market. What is the beta of stock Y$?$

$-1\mathrm{.}00$

$-0\mathrm{.}75$

$1\mathrm{.}33$

$0\mathrm{.}00$

$0\mathrm{.}25$