The jamison family kept a log of the distance they traveled during a trip, as represented by the graph below. distance (1,40) (2,110) (4,180) (6,230) (8,350) (10,390) elapsed time (hours) during which interval was their average speed the greatest? (1) the first hour to the second hour (2) the second hour to the fourth hour (3) the sixth hour to the eighth hour (4) the eighth hour to the tenth hour