Currently, a company is selling 1,000 units of a certain commodity at a price of $5 per unit. The manager of the company estimates that the price is currently increasing at the rate of 5 cents per week, while demand is decreasing at the rate of 4 units per week.

a. If x is the level of production at time t, what is R(x)? Find the rate at which R(x) is currently changing with respect to x. Is the revenue currently increasing or decreasing?

b. At what rate is the average revenue R(x)/x currently changing? Is the average revenue currently increasing or decreasing?