, 2016

When Hicham runs 10 km at an average speed of 12 km/h, he takes $\frac{10}{12} = \frac{5}{6}$ hours to run this distance.

Since Hicham runs for a total of 1.5 hours, then he runs the last 6 km in $\frac{3}{2} - \frac{5}{6} = \frac{9}{6} - \frac{5}{6} = \frac{4}{6} = \frac{2}{3}$ hours.

Since he runs 6 km in $\frac{2}{3}$ hours, his average speed for this segment is $\frac{6}{2/3} = 9$ km/h.