Question

In a race, the mean time for three runners was 12.4 seconds and the mean

time for another six runners was 11.5 seconds. Calculate the mean time for
all the nine runners

Answer 1

11.8

Explanation:

3(12.4) + 6(11.5) = 37.2 + 69 = 106.2

106.2/9 = 11.8