Here are two problems, or puzzles. In each case, we'll examine some alternatives and
work toward a rational choice.
Choose a container suitable for carrying 3 pounds of bacon home from the grocery store,
a distance of about a mile.
Alternative A: Plastic grocery bag. Weighs 0.2 ounces. Costs 0.3
cents. Waterproof. Has built- in handles. Made of a synthetic material derived from oil, a
non-renewable resource. Can be reused an average of 4 times. Not biodegradable. Can be
recycled, but only with some difficulty, and not in every community.
Alternative B: Paper grocery bag. Weighs 2 ounces. Costs 0.5 cents.
Larger volume. No handles. Made of an organic material from renewable resources. Can be
reused only one time. Biodegradable. Easily recycled in almost every community.
Alternative C: Cloth grocery bag. Weighs 4 ounces. Costs $4. Large
volume. Has handles. Made of an organic material. Can be re-used almost endlessly. Slowly
biodegradable. Easily recycled once it's finally worn out.
Alternative D: Super-High-Tech metal grocery transporter cart. Weighs
45 pounds. Costs $225. Because of weight, needs power assist. Since power is built-in, may
as well include lights and a radio. 10 year life, but subject to mechanical breakdowns
which require a trained repair person. Can ultimately be recycled once repair costs get
out of hand.
Now the question. It's not to choose the best grocery
carrier. Our task is to choose the worst.
But that's too easy, right? Why pay $225 and get 45 pounds of complication to move a
payload of 3 pounds? That's $75 of machine cost and 15 pounds of machine weight to move
each pound of payload! That's clearly ridiculous! That super-high-tech grocery transporter
OK, on to Problem #2:
Choose a vehicle to move a 197 pound person and 3 pounds of bacon home from the
Alternative A: Bicycle. Weighs 30 pounds. Costs $500. Uses zero fuel. Causes
no pollution. Perfectly quiet. Simple design, requires little maintenance, most of which
can be done at home. Provides much-needed exercise.
Alternative B: Small motorcycle. Weighs 300 pounds. Costs $5000, plus
license and insurance, etc. Runs on gasoline, gets good mileage. Produces pollution and
noise. Subject to mechanical breakdowns which require a trained repair person.
Alternative C: Automobile. Weighs 3000 pounds - that is, 15 pounds for each
pound of payload. Costs $15000 - that is, $75 for each pound of payload, plus license,
insurance, etc. Runs on gasoline, and mileage is nothing to brag about. Produces pollution
and noise, plus danger to children and other pedestrians. Subject to mechanical breakdowns
which require a trained repair person.
Our choice? Obviously, we need to reject the device that weighs 15 pounds for every
pound of payload. Obviously we need to reject the device that costs $75 for every pound of
OK, back to reality. How are you going to get to the grocery