Patola Co. has an equipment costing P900,000 with an estimated salvage value of P90,000 and an estimated useful life of eight years. After using and depreciating the asset for the past two years, the company upgraded the machine parts and the cost of upgrading amounting to P100,000. Assuming that the upgrade reduces the operating cost of Patola Co., how much is the carrying value of the asset at the end of year 4? Assuming that the upgrade increases the useful life of the asset by two years of Patola Co., how much is the depreciation expense for the third year