A comet is moving at 1.2 x 108 m/s relative to a piece of
aerolite. The aerolite is moving at a velocity of 5.4 x 107 m/s
relative to the earth. What's the velocity of the comet relative to
the earth? Estimate the speed of light in a vacuum as 3.00 x
108 m/s and keep 3 significant figures.