Adeli sells two types of sandwiches, tuna salad and blt. the profit on the sandwiches is $1.50 for tuna and $2.50 for the blt. the amount of bread available is enough for 30 sandwiches. the deli has 4 hours available to prepare sandwiches in the morning. if tuna sandwiches take 6 minutes to prepare, and blt sandwiches take 9 minutes, how many of each type of sandwich should be prepared to maximize the profit?