Answer this for my cousin?

Question

Mr.Green is putting lights around 8 windows. Each is window is 3 and 1/2 feet wide and 5 feet long, How many feet of lights does he need?

Answer 1

Each window has perimeter as :

=2(3 1/2) + 2(5)     

=2(7/2) + 10

=7+10

=17

So, Each window`s perimeter is 17 feet

Here Mr.Green is puttiing lights around 8 windows

8(17)= 136 feet

So, he need 136 feet of lights