In the cafeteria, 100 milk cartons were put out for breakfast. After breakfast there were 40 milk cartons left. What is the ratio of milk cartons taken to total milk cartons put out for breakfast.
There were 100 milk cartons there and someone took 100-x=40. Add 100 on both sides 40-100=-60 so 60 milk cartons were taken. So the ratio would be 60:100, which can be simplified further 30:50 15:25 3:5.
