The average speed of the car is equal to the distance covered by the car (S=980 km) divided by the time taken (t=11 h):
[tex]v= \frac{S}{t}= \frac{980 km}{11 h}=89.1 km/h [/tex]
we can also convert this value into m/s, keeping in mind that
[tex]1 km = 1000 m[/tex]
[tex]1h=60\cdot 60 s=3600 s[/tex]
So we have
[tex]v=89.1 \frac{km}{h} \cdot \frac{1000 m/km}{3600 s/h}=24.75 m/s [/tex]
