First, we have to transform 23 minutes into hours, knowing that 1 hour is equivalent to 60 minutes.
[tex]23\min \cdot\frac{1h}{60\min }=0.38h[/tex]Then, we add this time to 2 hours to get 2.38 hours in total.
Now, we divide the distance traveled by the time spent to get the average speed.
[tex]\begin{gathered} v=\frac{46.7\operatorname{km}}{2.38h} \\ v=19.62(\frac{km}{h}) \end{gathered}[/tex]