The graph shows the price, in dollars, of different numbers of sweet breads at Alan's store. The table shows the price, in dollars, of different numbers of shortcakes at the same store.


Shortcake

Number
of Shortcake Price of Shortcake
(dollars)
5 45
10 90
15 135
20 180


How many dollars more is the price of a shortcake than the price of a sweet bread at David's store?