Help! cant solve this

Question

A small plane leaves an airport and flies north at 240 mph. A jet leaves the airport 30 minutes later and follows the small plane at 360 mph. How long did it take the jet to overtake the small plane?

Answer 1

Distance = (Rate)(Time)

The jet catches up when the distances are equal.

Let x = time (in hours) travelled by the plane.

Then x - 1/2 = time travelled by the jet. (30 min = 1/2 hour)

So, find x so that 240x = 360(x - 1/2).