Question

A train travels 63 kilometers in 2 hours, and then 56 kilometers in 3 hours. What is its average speed? i need the answer and units please

Answer 1

The average speed is the ratio between the total space and the total time of the motion:
$v= \frac{S_{tot}}{t_{tot}}$
The total space is 
$S_{tot}=63 km + 56 km = 119 km$
while the total time is 
$t_{tot}=2h+3h = 5h$
So, the average velocity is
$v= \frac{119 km}{5 h} =23.8 km/h$

We can also rewrite it in m/s. The total space is $S_{tot}=119000 m$, while the time is $t_{tot}=5h\cdot 3600 s/h = 18000s$, and so
$v= \frac{119000m}{18000s}=6.6 m/s$