In a portfolio problem, $x1,x2,$ and $x3$ represent the number of shares purchased of stocks $1,2,$ and $3,$ which have selling prices of $$15,$$$47\mathrm{.}25,$ and $$110,$ respectively. The investor has up to $$50,000$ to invest.

The expected returns on investment of the three stocks are $6\%,8\%,$ and $11\%.$ An appropriate objective function is: