8.Rashmi has a road map with a scale of 1 cm representing 18 km. She drives on a road for 72 km. What would be her distance covered in the map?

Given: Scale of 1 cm represents 18 km.So, let x cm be the distance covered in the map for the drives of 72 km on a road.
We can see that this is the case of direct proportion,So we have

\(\frac{1}{x}=\frac{18}{72}\)

\(\Rightarrow 18x= 1\times72\)

\(\Rightarrow x= \frac{ 1 \times72}{18}\)

\(\Rightarrow x=4cm\)

Hence, for 72km of distance we have 4 cm of scale.