I am flying a kite. The kite is moving horizontally at $151.5m$ above the ground. If the speed of the kite is $10m/s$. How fast (in m/s) is the string being let out,when the kite is $250m$ from me ? (assuming my height to be$1.5m$) ?

Try for some more interesting problems of Limits and Derivatives.

Your answer seems reasonable.
Find out if you're right!