A -ft streetlamp stands on level ground

MATHEMATICS · Single correct · CBSE · Mathematics · Applications of Derivatives · Applications of Derivatives

Problem

12

-ft streetlamp stands on level ground. A

5

-ft tall person walks directly away from the lamp at

3\text{ ft/s}

. How fast is the tip of the person’s shadow moving when the person is

8\text{ ft}

from the base of the lamp? (a)

\dfrac{15}{7}\text{ ft/s}

(b)

\dfrac{51}{7}\text{ ft/s}

(c)

\dfrac{36}{7}\text{ ft/s}

(d)

\dfrac{17}{4}\text{ ft/s}