IKMC 2009 - Grades 11-12 - Paper 01 - Self-study Question 1

There are 200 fish in an aquarium. 1% of them are blue; all the rest are yellow. How many yellow fish must be removed so that “the fish represent 2% of all aquarium fish”?

Editorial clarification: the source omits “blue” before “fish”. Read the target as blue fish being 2% of the fish remaining.