A pastry store wants to know how many dozen muffins to bake each day. Every dozen they sell fresh in the shop returns a profit of $5.00. Every dozen they bake but to not sell on the day they are baked is given to a local charity at a loss of $3.00 a dozen. The business is fairly stable in that they never sell less than 50 dozen nor more than 80 dozen muffins. Their sales history, rounded to the nearest ten dozen muffins is as shown:

Dozens of Muffins Sold