Final answer:
Christen is the runner winning now in the race.
Step-by-step explanation:
In order to determine which runner is winning, we need to compare the fractions that represent the distance each runner has run so far.
Anna has run 1/3 of the 2-mile race, which is equal to (1/3) x 2 = 2/6 miles.
Christen has run 1 1/8 of the 2-mile race, which is equal to (1 + 1/8) x 2 = 18/8 miles.
Ben has run 1 1/3 of the 2-mile race, which is equal to (1 + 1/3) x 2 = 8/6 miles.
Mary has run 7/8 of the 2-mile race, which is equal to (7/8) x 2 = 14/8 miles.
Comparing the distances, we can see that Christen has run the farthest so far, with a distance of 18/8 miles. Therefore, the runner winning now is Christen.