Answer:
Depreciable cost = Cost of equipment - residual value
Depreciable cost = 66,600 - 4,400
= $2,200
Annual depreciation = cost - residual value / useful life
Annual depreciation = 66,600 - 4,400 / 5
= 12,440
Straight-line rate = Annual depreciation expense / cost - residual value
Straight-line rate = 12,400 / 66,600 - 4,400
= 0.199