Suppose that the profit (in dollars) from the sale of Kisses and Kreams is given by
P(x, y) = 10x + 6.4y - 0.001x2 - 0.025y2
where x is the number of pounds of Kisses and y is the number of pounds of Kreams. Find P y, and give the approximate rate of change of profit with respect to the number of pounds of Kreams that are sold if 100 pounds of Kisses and 16 pounds of Kreams are currently being sold. What does this mean?