Question: Tires that fail in service result in significantly higher replacement costs than those replaced before failure. For an 18-wheeler (that is, a truck with 18 tires), failure on the road costs $300, whereas all 18 tires can be replaced prior to failure at a cost of $75 per tire. The probability of failure is given in the following table.
If tires are replaced at multiples of 5,000 miles only, what is the optimal age replacement policy?