Step-by-step explanation:
The area A of the tire in contact is 7"×5" = 35 sq inches and we know that each tire has a pressure of 30 psi so the weight of the car in tons is
[tex]W = \dfrac{APN}{2000} = \dfrac{(35\:\text{in}^2)(30\:\text{lbs/in}^2)(4)}{2000}[/tex]
[tex]\:\:\:\:\:= 2.1\:\text{tons}[/tex]
