Reagan's school has a fish tank with a total of 280 fish of two types, koi fish and goldfish. Over the next 3 weeks, the school added 2 koi fish and 5 goldfish per day. If the tank had 200 goldfish at the end of the three weeks, what's the total number of koi fish in the tank after the three weeks?
Please reason step by step, and put your final answer within \boxed{}.
user