So lets say the number of hamburgers sold is x. It says the number of cheeseburgers sold was 2 times the number of hamburgers, or 2x. The problem also say that the number of hamburgers plus cheeseburgers sold was 402. This means 2x + x = 402, or 3x = 402. Divide both sides by 3 and you get x = 134. So there are 134 hamburgers sold.
