a$)$ What are the machines below to be selected. If return of $18\%$ per year is required, answer the following.

b$)$ Using PW the payback periods of the machines?

$\backslash$table$[[,$Machine $1,$Machine $2],[$Initial Investment, $$,4,500,7,000],[$Annual Net Income, $$,1,550,1,500($years $1-6)],[,,4,000($years $7-10)],[$Life$,$ years,$5,10]]$