Vivian went on a bicycle trip through Germany with her family. One afternoon, she rode her bicycle along a long flat road at a constant speed for 24 kilometers (km). The ride took her 1.2 hours (h). At what speed did she ride her bicycle? A. 0.05 h/km B. 20 mi/h C. 20 km/h D. 28.8 km•h

d = distance traveled by her on her bicycle on a long flat road = 24 kilometer

t = time taken by her to travel distance "d" on her bicycle on a long flat road = 1.2 hours

v = average speed of vivian = ?

we know that average speed is given as

v = d/t

inserting the values in the above formula

v = 24 kilometer / 1.2 hour

v = 20 kilometer/hour

hence the correct choice is

C) 20 km/h