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
![speed=(distance)/(time)]()
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.