I need help, this is confusing, and whenever I try getting help my comment is ignored and someone sends me an annoying link.

Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. how many hours after the truck's departure will the two meet?

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'

Are the corresponding angles congruent? explain why or why not.