Me je ne comprends pas comme le résoudre.

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?

What is the solution to this system of equations? y= 2x - 3.5 x - 2y = -14

Apackage of five erasers cost 0. $.39 at this rate how many how much would 60 erasers cost in dollars and cents