The figure illustrates a graph of price versus quantity of brownies. The horizontal axis is labeled Quantity (dozens of brownies per day), and ranges from 0 to 8 in increments of 1 unit. The vertical axis is labeled Price (cents per brownie), and ranges from 30 to 100 in increments of 10 units. A straight line labeled D starts from the point (1, 90), moves toward the lower right, and ends at the point (6, 40). A straight line labeled S starts from the point (2, 40), moves toward the upper right, and ends at the point (7, 90). Both the graphs intersect at the point (4, 60) depicted by a dot. Two dotted lines from the dot move perpendicular to the horizontal and the vertical axes, respectively. 0 1 2 3 4 5 6 7 8 30 40 50 60 70 80 90 100 Quantity (dozens of brownies per day) Price (cents per brownie) The figure illustrates a graph of price versus quantity of brownies. The horizontal axis is labeled Quantity (dozens of brownies per day), and ranges from 0 to 8 in increments of 1 unit. The vertical axis is labeled Price (cents per brownie), and ranges from