A restaurant serves two dishes. Tuna and eel. The cost of a tuna is $7. The cost of an eel is $10. What is their minimum cost per day? Their supplier will sell them at least 15 tuna and at most 50. The same supplier makes them buy at least 20 eel but has a limit of 70. But, to end with a profit each day they have to sell at LEAST 60 dishes a day.