Answer:
5 hours
Explanation:
First of all, Joe goes 20 mi per 2 hours. If you divide the 20 by 2, it takes Joe 1 hr to drive 10 mi. So, If you add 2hr by 2 hr, then you get 4 o mi. Then, add 1 more hour, then you get 20+20+10=50. It takes him 5 hours to go 50 mi.