Blue Ridge Power Company has a maximum capacity of 2.5 million kilowatt-hours (kWh) of electric power available on a daily basis. The demand (in millions of kWh) for power from its customers for high-demand (peak) hours and low-demand (off-peak) hours is determined by the following formulas:

high demand: 5.8 - 0.06p_h + 0.005p_l

low demand: 3.0 - 0.11p_l + 0.008p_h

The variable p_l equals the price per kilowatt-hour during low-demand hours, and p_h is the price per kilowatt-hour during high-demand (peak) hours. Formulate and solve a nonlinear programming model to determine the price structure (per kWh) that will maximize revenue.