Eric is starting his own business by baking muffins and cupcakes at a local farmers' market. To make it worth his time, he needs to sell at least 10 cupcakes, but can bake no more than 50. He must also sell at least 20 muffins but can bake no more than 70. Eric cannot bring more than 90 muffins and cupcakes in total to the market. Eric makes $4 from each cupcake and $3 from each muffin. How many cupcakes and muffins should he sell to make the maximum profit