Physics question?

http://learn.flvs.net/webdav/assessment_images/educator_physics_v5/M2v5_1.gif

An object began moving at the starting point (0, 0) on the graph. The average speed (in mph) of the object for the entire trip of 5.0 hours is

15mph
17mph
19mph
20.0mph
22mph


80/5 is 16.. but thats not a choice??
Update: http://postimg.org/image/fa0203bqj/ -- graph
4 answers 4