Suppose Jan and Tina decide to start a small business selling turquoise belts in Miami International Airport. To get into the business they need to invest in a fancy push cart. The price of the push cart is $20,000 with all the display attachments built in. Suppose that Jan and Tina estimate that they will sell 3,000 belts each year for $10 each. Further assume that each belt costs $5 from the supplier. Finally, the cart must be staffed by one clerk, who works for an annual wage of $14,000. Alternatively, Jan and Tina could realize a 10% return if they invest in corporate bonds as against a push cart.