Dave Drexel has received a $60,000 inheritance and will invest all of it. His investment options are a certificate of deposit paying 6% after one year, a venture capital project paying a minimum of 3% (but with a potential maximum return of 10%) after one year, and a natural gas exploration company.. Although his investment in the natural gas company could yield a 100 % one-year return, Dave could also lose everything he invested in the company. Help Dave maximize the potential value of his investment after one year, given the following criteria: 1) No more than $30,000 may be invested in the natural gas exploration company 2) At least $20,000 should be invested in the certificate of deposit 3) The value of the portfolio must be at least $40,000 at the end of the investment period (he is not willing to lose more than $20,000) 4) All of the inheritance must be invested