First, let's calculate the volume of dirt that would have to be removed to dig the foundation.
[tex]\begin{gathered} 30ft\rightarrow10yd \\ 15ft\rightarrow5yd \\ 3ft\rightarrow1yd \\ \\ 10yd\cdot5yd\cdot1yd=50yd^3 \end{gathered}[/tex]Therefore, 50 cubic yards would have to be removed in order to dig the foundation.
Now, let's use a rule of three to calculate the loads needed to move such volume of dirt:
This way,
[tex]x=\frac{50}{5}\rightarrow x=10[/tex]10 loads would be needed.
To calculate the total cost, multiply the cost per load by the number of loads:
[tex]10\cdot20=200[/tex]Therefore, it would cost the contractor $200 to get all the dirt hauled away