Few companies take the time to estimate the value of a good customer (and often spend little effort to keep one). Suppose that a customer at a restaurant spends, on average, R per visit and comes F times each year (for example, if a customer purchases once every two years, then F=7=0.5. The restaurant realizes a gross profit margin of M (expressed as a fraction) on the average bill for food and drinks. In addition, the fraction of customers defecting (not returning) each year is D. Complete parts a and b. a. Develop a mathematical model to compute V, the gross profit during a customer's lifetime in doing business with the restaurant (this is often called the economic value of a customer). V =] (Simplify your answer.)