#### Problem 15E

(a) What quantities are given in the problem?

(b) What is the unknown?

(c) Draw a picture of the situation for any time $t$.

(d) Write an equation that relates the quantities.

(e) Finish solving the problem.

15. A street light is mounted at the top of a 15 -ft-tall pole. A man $6 \mathrm{ft}$ tall walks away from the pole with a speed of $5 \mathrm{ft} / \mathrm{s}$ along a straight path. How fast is the tip of his shadow moving when he is $40 \mathrm{ft}$ from the pole?