On January 1, 2022, a company purchased a patent for $100,000. The patent has a useful life of 10 years. The company uses the straight-line method of amortization.

a) Calculate the annual amortization expense of the patent.
b) On January 1, 2025, the company determines that the patent has only 3 years of remaining useful life. Recalculate the annual amortization expense for 2025 and the subsequent years.