A number plus 7 is at most 4

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. what distance from city a is the point where the truck and the car will meet?

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

Write 5(6x+4)-2(5x-2) in the form a(bx+c) where a,b and c integers and a> 1