Answer
34 tickets
Work Step by Step
We know that the drama club wants to raise "at least" 500 dollars, so the right side of the equation will look like $\geq$ 500. The members already sold 50 tickets at 5 dollars, so that is 250 dollars. Now, the standard ticket costs 7.50 dollars, so how many of these tickets plus the already sold tickets need to be sold to reach 500 dollars? The new equation that needs to be solved is 7.50x+250$\geq$500. Subtract 250 from each side of the equation and then divide by 7.50. The new equation becomes x$\geq$33$\frac{1}{3}$. Since you can't sell a third of a ticket, at least 34 more tickets need to be sold.