Need help with A b & C. Thanks A) the rate of total revenue is $___ per dayB) The rate of change of total cost is $___ per dayC) The rate of change of total profit is $___ per day

Find the rate of change of total revenue, cost, and profit with respect to time. Assume that R(x) and C(x) are in dollars. R(x) = 55x - 0.5x , C(x) = 5x + 20, when x = 35 and dx / dt = 30 units per day . . . The rate of change of total revenue is $ per day