Tamias Company purchased equipment that cost $839,000 on January 1, 2015. The entire cost was recorded as an expense. The equipment had a seven-year life and a $41,000 salvage value. Tamias uses the straight-line method to account for depreciation expense. The error was discovered on December 12, 2018. Tamias is subject to a 36% tax rate.

a) By how much was Tamias' net income for the year ended December 31, 2015, understated?

b) Before the correction was made and before the books were closed on December 31, 2018, by how much were retained earnings understated?