Given:
The number in the highlighted cell is 18.
The total sales revenue of pluto cars is 80.
To find the relative frequency from the sales of sedans by Plato cars to the total sales revenue of Plato cars:
The formula for relative frequency is,
![\begin{gathered} RF=\frac{subgroup\text{ fr}equency}{\text{Total frequency}} \\ =(18)/(80) \\ =0.225 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/4l7780m5aile21trsmkivgmkb5wazesgeh.png)
So, the relative frequency is 0.225.
Hence, the answer is,
The number in the highlighted cell is 18. The relative frequency from the sales of sedans by Plato cars to the total sales revenue of Plato cars is 0.225