<span>If the tip, t, varies directly with the number of guests, g, then it means that any change in tip there is a corresponding change in the number of guests. When the tip increases the number of guests increases as well. Therefore,
t </span>α g
To change the it to equal sign, we incorporate a proportionality constant, k.
t =<span> kg </span> This equation will represent the relation of t to g.