To find out how much money the charity raises by selling a single ticket, we can look at the equation for profit:
\[ P = 70n - 1500 \]
Here, \(n\) represents the number of tickets sold, and \(P\) is the profit. The term \(70n\) indicates the total income from selling \(n\) tickets, where each ticket is sold for \(70\) dollars.
Therefore, the amount of money the charity raises by selling a single ticket is:
\[ \text{$}70 \]
Thus, the charity raises \($70\) by selling a single ticket.