A camper is trying to start a fire by focusing sunlight onto a piece of paper.?

A camper is trying to start a fire by focusing sunlight onto a piece of paper. The diameter of the sun is 1.39 x 10^9 m, and its mean distance from the earth is 1.50 x 10^11 m. The camper is using a converging lens whose focal length is 11.5 cm. (a) What is the area of the sun's image on the paper? (b) If 0.718 W of sunlight p through the lens, what is the intensity of the sunlight at the paper?