You and your friends have decided to build a skateboard ramp behind your house. You have already purchased $500 in materials and are considering renting an electric saw.
It costs $20/hr to rent an electric saw. You estimate it will take 6 hours to build the ramp. If you decide to use your saw, which is a handsaw, you will not have to pay anything to rent an electric saw, but it will take 15 hours to build the ramp. Regardless of the decision, you will need to ask for time off from your job, which pays $8/ hour.