An athlete runs 3 kilometers at a constant speed of
5 meters per second and then 7 kilometers at a
constant speed of 14.4 km/hr. What is the aver-
age speed of the runner during her 10 km run?
(A) 0.52 m/s
(B) 1.94 m/s
(C) 4.26 km/hr
(D) 15.3 km/hr

1 kilometer = 1000