Cylinder A has radius r and height h as shown in the diagram. Cylinder B has radius 2r and height 2h. How many times greater is the surface area of Cylinder B than the surface area of Cylinder A?

Surface area of a cylinder: 2*pi*r^2+2*pi*r*h.
Surface area of Cylinder B: 2*pi*(2r)^2+2*pi*2r*2h
=8*pi*r^2+8*pi*r*h. Therefore Cylinder B is 4 times the surface area of cylender A