Question: A grocer’s daily profit from the sale of two brands of apple juice is P(x,y) = (x-30)(70-5x+4y)+(y-40)(80+6x-7y) cents, where x is the price per can of the first brand and y is the price per can of the second. Currently the first brand sells for 50 cents per can and the second for 52 cents per can. Use marginal analysis to estimate the change in the daily profit that will result if the grocer raises the price of the second brand by 1 cent per can but keeps the price of the first brand unchanged.