Find yhe difference 2/5 - 3/10

How do you use the elimination method for this question? explain, because i really want to understand!

1mile equals approximately 1.6 kilometers. which best approximates the number of miles in 6 kilometers?

Abird on top of a 200 ft bridge tower sees a man standing on the lower part of the bridge (which is 50 ft above the ground). the angle of depression from the bird is 26 ̊. how far is the man from the base of the bridge tower? with explanation and pictures .