[tex]\begin{gathered} \text{The scale on the map shows the ratio of } \\ 1\operatorname{cm}\colon13\text{miles} \\ \text{If two cities are 104 miles apart, then the distance as per ratio given is;} \\ x\text{ cm=}\frac{104miles}{13miles} \\ x\text{ cm=8cm} \\ \text{The cities therefore would be 8 cm apart on a map} \end{gathered}[/tex]