Please show me the solution for: Vinny weighed 300 pounds then lost 20 pounds in the first month of his diet. He continued his diet but each month, he lost half as much weight as he had lost in the previous month. At the start of the fifth month of his diet, he worked harder to lose extra weight then decided to end his diet. If Vinny weighed 250.5 pounds at the end of his diet, how many pounds did he lose throughout the fifth month?