Level 3 4 m
Henry had to paint some cartons. On the first day, the number of cartons he painted was 40% of the number of cartons that he had not painted. One week later, he painted another 100 cartons. As a result, the total number of painted cartons became 28 more than 12 of the total number of cartons. How many more cartons were unpainted than painted on the first day?