Prepare the following journal entries and calculations:

a) A patent that was acquired for $100,000 at the beginning of the current year expires in 15 years and is expected to have value for 4 years. Present the adjusting entry to amortize the patent for the current year.

b) Mineral rights on an ore deposit estimated at 4,000,000 tons of ore were acquired for $4,000,000. Present the adjusting entry to record depletion for the current year, during which 350,000 tons of ore were removed.

c) Legal costs incurred to defend the rights that patent provided were $42,000. The patent only has a legal life of 5 years. Determine the amount to be amortized for the current fiscal year.