A balloon is at a height of 50 meters and it is rising at the constant rate of 5 m/sec. A bicyclist passes underneath it, traveling at a speed of 10...

A balloon is at a height of 50 meters and it is rising at the constant rate of 5 m/sec. A bicyclist passes underneath it, traveling at a speed of 10 m/sec. How fast is the dsitance between the bicyclist and the balloon increasing 2 seconds later? I have tried various ways to answer this but cannot figure it out.