2018 AMC 12A Problems/Problem 1
Problem
A large urn contains balls, of which
are red and the rest are blue. How many of the blue balls must be removed so that the percentage of red balls in the urn will be
? (No red balls are to be removed.)
Solution
There are red balls; for these red balls to comprise
of the urn, there must be only
blue balls. Since there are currently
blue balls, this means we must remove