Range Finder Rating Hard Derivative/ Related Rates Problem?

Hard derivative/ related rates problem? - range finder rating

A hot air balloon, a plane field increases, followed by the search range of 500 meters from the starting point. If the elevation angle is the rangefinder (pi / 4), the angle is always rad / min at a rate of 014 /. How fast is the ball?

Note: I ask this problem, so I can find a way to do it to not cheat. Any help would be appreciated. Thank you!