Nina likes to tip restaurant staff 18% when she enjoys the meal and has good service. Which expression represents the amount of tip, in dollars, that Nina will give when she has a positive experience eating a meal that cost n dollars?

For this case we are going to use the following variables:

y = amount in $ of tip.

x = amount in $ that Nina must pay to eat a meal.

The mathematical expression will be

y = 0.18x

For example if Nina pays $ 100 for a meal, then the tip is:

y = 0.18 * (100)

y = 18 $

Answer:

An expression represents the amount of tip, in dollars, that Nina will give when she has a positive experience eating a meal that cost n dollars is:

y = 0.18x