To determine the number of tickets sold last week, we can set up the following equation based on the information provided:
Let \( x \) be the number of tickets sold last week. According to the problem, 300 tickets sold this week is 120 percent of the tickets sold last week. This can be expressed as:
\[ 300 = 1.2x \]
To find \( x \), we can solve for \( x \) by dividing both sides of the equation by 1.2:
\[ x = \frac{300}{1.2} \]
Calculating the right side:
\[ x = 250 \]
Therefore, the number of tickets sold last week for the school play was 250 tickets.