The satisfaction we get by the combination of eating pizza and drinking soda is that in which we are able to eat more pizza and still have money left to conclude the session with a soda. With this, only one soda is needed.
With the given amount for soda and each slices of pizza, one can get the satisfaction by eating 9 slices of pizza for $18 and drinking one can of soda for $1. This then would total to $19.
