What is the depreciation for 2020 using the sum of years' digits?

Captive Company purchased a factory equipment on October 1, 2020 costing P960,000.In view of pending technological developments it is estimated that the machine will have a resale value upon disposal in four and one half years of P70,000 and the disposal cost will be P10,000. What is the depreciation for 2020 using sum of years' digits? * 180,000 75,000 90,000 45,000