All helicopter leaves central airport and flies North at 180 mph. 20 minutes later a plane leaves the airport and follows the helicopter at 330 mph. How long does it take the plane to overtake the helicopter?
Let the time taken by plane to overtake the helicopter be t.
distance = speed * time
When the plane overtakes the helicopter, the two distances are equal.
180 * (t + 20/60) = 330 * t
180 t + 60 = 330 t
150 t = 60
t = 60/150 = 0.4 hr = 24 minutes.