Ali and Sara ate 80 small apples combined. Ali ate 4 times more apples than Sara. How many apples did Sara eat?
Let A be the number of apples Ali ate and S be the number of apples Sara ate.
We have: A + S = 80 apples.
And: A = 
<gadget id="calculator">4</gadget>
<output>4</output>
4S.
Which means: 4S + S = 80.
So: 5S = 80.
So the number of apples Sara ate is: S = 80 / 5= 
<gadget id="calculator">80/5</gadget>
<output>16</output>
16 apples.

<result>16</result>