18.) The first costs of an equipment is P 65,000 and a salvage value of P 3,000 at the end of its 6 - year life. Find the book value after 4 years using the Sinking Fund Method at 10%. Select one: a. P 27,707 b. P 7,435 c. P 8,036 d. P 37,293 19.) An engineer bought an equipment for P 500,000. Other expenses including installations amounted to P 30,000. The estimated useful life of the equipment is 10 years. The salvage value is x% of the first cost. Using the straight line of depreciation, the book value at the end of 6 years will be P 291,500. What is the value of x? Select one: a. 10 b. 25 c. 12 d. 20