Ahelicopter leaves rogers airport and flies north at 180 mph. one hour later a plane leaves the airport and follows the helicopter at 330 mph. how long does it take the plane to catch up to the helicopter?

Distance = speed * time

The plane catches the helicopter when they both traveled the same distance, d.
The helicopter traveled t hours, but the plane traveled 1 hour less, or t - 1 hours.

helicopter:
d = 180t

plane:
d = 330(t - 1)

The distance they both traveled, d, is the same, so

180t = 330(t - 1)

180t = 330t - 330

-150t = -330

t = (-330)/(-150)

t = 2.2

The helicopter traveled 2.2 hours, so the plane traveled 1.2 hours.

The plane catches the helicopter after 1.2 hours of plane flight.

Subtracting is the opposite of adding

Google it that might work