Part A: Is Casey's answer correct or incorrect? If it is incorrect, explain why it is incorrect and show the correct steps to solve the equation. (6 points)
Part B: How many solutions will this equation have?
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?