Can someone explain how they got the number $10$for depreciation per unit? TIA

$$3,000.$ The equipment operated for $180$ hours the first year, $540$ hours the second year, $720$ hours the third year, and $360$ hours the fourth year.

Read the requirements.

Prepare a depreciation schedule using the units$-$of$-$production method.

Units$-$of$-$Production Depreciation Schedule