The total number of days in 3 weeks is 3 * 7 = <<3*7=21>>21 days.

If 2 koi fish are added every day, the total after 21 days is 21 * 2 = <<21*2=42>>42 koi fish.

if 5 goldfish are added every day, the total after 21 days is 5 * 21 = <<5*21=105>>105 goldfish.

The total number of fish in the tank after 3 weeks is 280 + 42 + 105 = <<280+42+105=427>>427 fish.

If there were a total of 200 goldfish in the tank after 3 weeks, then the number of koi in the tank is 427 - 200 = 227 koi fish.

# Answer

227
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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?
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227
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?
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