Things we know: every pound of cherries cost four dollars.
We don't know how much the mother got and it is represented by the variable 'r'. But we do know how many pounds the dad got. He got two pounds.
We know the total cost the mom had to pay which is 4 * r and the amount the dad paid is 4 * 2 or 8.
Now we want to make an algebraic expression that represents how much more the mother paid than the father.
Final answer:
8 - (4 * r)
Hope this helps!