POTW116

On a plane, two men had a total of 135 kilograms of luggage. The first paid $12 for his excess luggage and the second paid $24 for his excess luggage. Had all the luggage belonged to one person, the excess luggage charge would have been $72. At most how many kilograms of luggage is each person permitted to bring on the plane free of additional charge?

This is problem 30 from the 1995 SMO Junior Round 1.