If $6\text{cm}$ represents $50\text{km}$ on a map and the actual distance between two towns is $125\text{km}$, then their distance apart on the map is ． 
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If $$6\textasciitilde\text{cm}$$ represents $$50\textasciitilde\text{km}$$, $$3\textasciitilde\text{cm}$$ represents $$25\textasciitilde\text{km}$$. So, their distance apart on the map is $$125\div25\times 3=15\textasciitilde\text{cm}$$. 