For this case, the first thing we must do is define variables: x: unknown number (1) y: unknown number (2) We now write the equations that model the problem: their sum is 6.1: their difference is 1.6: Solving the system we have: We add both equations: Then, we look for the value of y using any of the equations: Answer: The numbers are:
If you think about how it works when cups are stacked. you will begin with the height of the cup plus the height of the lip you would then add just the heigt of the lips until you get to the height needed. so your answer should be 19 cups