How do I calculate peak and off-peak demand?

using these formulas -->

Suppose there are two electricity generation technologies in Texas: coal and combined-cycle gas (CCGT). Coal has 100MW of capacity at a marginal cost of $20/MWh and CCGT has 50MW of capacity at a marginal cost of $30/MWh. For now, assume that the market is perfectly competitive.

Demand for electricity is P = 100 - 2Q during off-peak hours and P = 200 - Q during peak hours (where Q is in MWh)