The first thing we have to do is identify our input units and output units in order to know the conversions.
![\begin{gathered} 1\operatorname{km}\to1000m \\ 1h\to60\min \\ 1\min \to1s \end{gathered}]()
Time to find the average speed of the car that travels 190m in 18s we have to divide them
We already have our average speed in meters per second, we convert them to time using the aforementioned conversions
![\begin{gathered} 10.55(m)/(s)*\frac{1\operatorname{km}}{1000m}=0.010556\frac{\operatorname{km}}{s} \\ \\ \end{gathered}]()
![0.010556\frac{\operatorname{km}}{s}*(60s)/(1\min)=0.633\frac{\operatorname{km}}{\min }]()
![0.633\frac{\operatorname{km}}{\min}*(60\min)/(1h)=38\frac{\operatorname{km}}{h}]()
The answer is: The car travels at an average speed of 38 km/h.