A baker can bake 20 cupcakes in two hours, 30 cupcakes in three hours, and 40 cupcakes in four hours.
so, the rate can be calculated as following:
number of cupcakes over the number of hours
So,
[tex]\begin{gathered} \frac{20}{2}=10 \\ or,\frac{30}{3}=10 \\ or,\frac{40}{4}=10 \end{gathered}[/tex]