To make sushi and sashimi, traditional Japanese dishes, you'll need fresh tuna, avocado, rice, seaweed, and soy sauce. With a budget of $60, fresh tuna costs $20, vegetables cost $5, rice costs $3, seaweed costs $4, and soy sauce costs $2. Sushi requires 1.2 units of tuna, 0.5 units of vegetables, 1 unit of rice, 1 unit of seaweed, and 0.3 units of soy sauce. On the other hand, sashimi requires 1.8 units of tuna and 0.2 units of soy sauce. Considering a total of 300 minutes available for preparation, sushi takes around 20 minutes, and sashimi takes about 15 minutes.

Knowing that your friends enjoy sushi 1.5 units and sashimi 1.2 units, maximize the total enjoyment by determining the quantities of sushi and sashimi to prepare, considering a single linear optimization problem with two decision variables.