In
the design of an automobile engine part, an
engineer has a choice of either steel casting or an aluminum alloy casting. Either machine provides the same service.
However, the steel casting weighs 8 ounces, compared with 5 ounces for the aluminum casting. Every pound of extra weight in
the automobile has been assigned a penalty of $6 to account for
increased fuel consumption
during the life cycle of the car. The
steel casting costs $3.20 per pound, while the aluminum allow can be cast for
$7.40 per pound. Machining cost per
casting are $5.00 for steel and $4.20 for
aluminum. Which material should the engineer select,
and what is the difference in unit costs? 1 pound = 16 ounce