60 cars per hour
1) Since we've been told there is a direct variation between the number of cars and the number of hours, the more worked hours the more cars are produced.
2) So let's check the graph to find the ratio. We can do that by locating the two points (1, 60) and ( 2,120).
Now let's write a ratio, between them the final number of cars built and the number of hours:
3) So the ratio is 60 cars per hour