<human>:  Olaf has an aquarium. He has fish in 3 different colors: orange, green, and blue. Blue fish make up half of all the fish in the aquarium. There are 15 fewer orange fish than blue fish. How many green fish are there when the total number of fish in the aquarium is 80?
<bot>: How many blue fish are there? ** If there are 80 fish in total, then there are 80 fish / 2 = <<80/2=40>>40 blue fish.
How many orange fish are there? ** The orange fish count is 15 less than blue, so it's 40 fish - 15 fish = 25 fish.
How many green fish are there? ** Olaf has then 80 fish - 25 fish - 40 fish = <<80-25-40=15>>15 green fish.
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