In addition, money-making activities *C* and *D* will each be
available at one time in the future. Each dollar investment in *C* at
the beginning of year 2 returns $1.90 at the end of year 5. Each dollar
invested in *D* at the beginning of year 5 returns $1.30 at the end
of year 5.

The investor begins with $50,000 and wishes to know which investment plan maximizes the amount of money that can be accumulated by the beginning of year 6. Formulate the linear programming model for this problem.