Answer:
after 6 hours
Step-by-step explanation:
Since no method is specified, we write a table.
After n hours distance car 1 distance car 2
0 0 0
1 40 miles 0
2 80 miles 0
3 120 miles 0
4 160 miles 60 miles
5 200 miles 120 miles
6 240 miles 180 miles
7 280 miles 240 miles
8 320 miles 300 miles
9 360 miles 360 miles
The second car leaves at hour 3 and catches up to the first car at hour 9.
9 - 3 = 6.
Answer: after 6 hours
