not using excel please. BY hand

A bottling machine was installed three years ago at a cost of $ 100,000. Today, the machine's market value is $ 30,000. The machine is expected to be operational for a maximum of four additional years. The yearly market values and operating costs of the existing machine are listed in the table below. The numbers are expressed in today's dollars. The investor uses an MARR of 7%/year. Years 1 2 3 4 5000 0 Market Value Annual Costs 12,000 20,000 10,000 25,000 35,000 35000 1- Calculate the economic service life and the associated AW* of the existing machine. 2- After investigating the market, you discover that the best available replacement option has an economic service life of 4 years and an associated AW* of costs of 35,000 USD. When should you replace the existing machine and why