This brief note provides a simple, yet powerful example of how the
marginal cost/marginal benefit principle can be used in everyday life.
Using the decision of the optimal choice of speed on the highway, this
note was developed for use as one of the first readings in an
introductory microeconomics course. It is clear in this demonstration
that marginal cost is increasing, while marginal benefit is decreasing,
and how the intersection of these two curves shows the optimal choice.
In addition, shifts in the curves can easily be demonstrated as an
introduction to supply and demand.