Luke is arranging for a party to be held in the students' union. The use of the hall will be free but security costs of 300 will have to be met. The cost of the main band will be 2,500 and the supporting band will cost 450. Tickets will be priced at 15 each. On arrival, every ticket holder will be given a bottle of water, worth 1 per bottle. If Luke sells 400 tickets as he anticipates, what profit will he make?

the answer is:

Profit will be (400-233) x (15-1) = 2,338.

I didn't understand the answer, maybe I don't know the right formula. Can you explain?