A street light is mounted at the top of a 15' pole. A man 6' tall walks away from the pole with a speed of 5 ft/s along a straight path. How fast is the tip of his shadow moving when he is 40 ft from the pole?
Apparently, I've been doing too many calculus problems of late because I read this as they are saying that a dude is walking at 5 ft/second and are asking me how fast his shadow is moving. How can this answer be anything other than 5 ft/s? They are obviously asking for dx/dt, but they give us dx/dt!!!
Can somebody set me straight so that I can tackle this problem. I am clearly missing something.