please help 13, 14 , 15 , 16

13. An annual deposit was made into an investment growing at 12% per year for 8 years. The amount accumulated will be withdrawn in a pattern following the linear gradient starting on the gin year until the 12h year. What is the value of "G" in the uniform gradient withdrawal? 14. If Php 1,000 becomes Php 5,743 after 15 years, when invested at an unknown rate of interest compounded semi-annually, determine the unknown nominal rate and the corresponding effective rate. 15. A man bought a lot worth Php 1,000,000 if paid in cash. On the installment basis, he paid a down payment of Php 200,000; Php 300,00 at the end of one year, Php 400,000 at the end of three years and a final payment at the end of five years. What was the final payment if interest was 20%? B. Depreciation 16. A company purchased a machine for Php150,000. It paid shipping costs of Php 10,000 and nonrecurring installation costs amounting to Php12,000. At the end of 3 years, the company had no further use of the machine, so it spent Php5,000 to have the machine dismantled and was able to sell the machine for Php50,000. The company had depreciated the machine on a straight-line basis using an estimated life of 5 years and P10,000 salvage value. By what amount did the recovered depreciation fail to cover the actual depreciation