D.4 Specialized bits (costing $50,000) used in the min- ing industry have a useful life of 5000 hours of op- eration and can be traded in when a new bit is purchased for 10% of first cost. The drilling machine that uses the bit is used 1000 hours per year. What is the equivalent uniform annual cost of these bits at 2.5%?
(a) $8559
(b) $9510
(c) $9828
(d) $10,920
D.5 A new chemical remediation tank is needed. Current technology tanks, which cost $150,000, must be drained and treated every 2 years at a cost of
$30,000; the tanks will last 10 years, and each will have a salvage value of 5% of first cost. A tank with