Facts from the problem:
Charges $6.50/hour
April = 30 hours worked x $6.50/hour = $195/hour
May = 35 hours worked x $6.50/hour = $227.50/hour
June = 45 hours worked x $6.50/hour = $292.50/hour
April/May = $195/227.50 = .857 = Catalina earned 86% of the total amount of money in April compared to May
May/June = $227.50/292.50 = .778 = Catalina earned 77% of the total amount of money in May compared to June.