Can someone please help me?

Question

A factory has 3 cylindrical chimneys to release waste gases. Each chimney is 150ft tall. The base of the chimney has a diameter of 15ft. A can of paint can cover 100 square ft of surface. How many cans of paint are needed to paint the outsides of all 3 chimneys? 

Answer 1

The surface area of each is π(7.5)²(150)

Multiply that by 3 (for three chimneys)

Then divide by 100.