A small manufacturer has net annual cash flows as follows over the first four years of business. The applicable interest rate varies from year to year. End of Year Cash Flow Interest Rate During Year Determine the present worth of the series. 0 1 2 3 4 $80,000 60,000 $10,000 $70,000 $100,000 5% 7% 7% 4% $106,457 $185,459 $100,274 $92,975