Speed of the truck driver: 2miles/hour
Since, he drives 2 hours each day, he would dirve:

Now, we multiplicate by 6 days:
4 miles *6= 24 miles --> the miles he will dirve per week, so now we multiplicate it by 3 weeks
24 miles*3=72 miles --> The miles he will drive per year, now we multiplicate it by 9 years!
72 miles *9=648 miles--> He would drive 648 miles in 9 years