Consumer Demand When the price of an essential commodity rises rapidly, consumption drops slowly at first. If the price continues to rise, however, a “tipping” point may be reached, at which consumption takes a sudden substantial drop. Suppose the accompanying graph shows the consumption of gasoline, $G(t),$ in millions of gallons, in a certain area. We assume that the price is rising rapidly. Here $t$ is the time in months after the price began rising. Sketch a graph of the rate of change in consumption as a function of time.