Final answer:
If 4 tickets at half-off cost $15, then the full price would be double, totaling $30. Dividing this amount by 4 results in each person paying $7.50 for their ticket at full price.
Step-by-step explanation:
The student's question tackles a scenario where 4 tickets at half-off amount to $15. To calculate each person's share if paying full price, we first need to determine the full price of the tickets. Since 4 tickets cost $15 at half-off, the full price for 4 tickets would be double that, which is $30. To find out how much each person would pay when sharing the cost equally, we divide the total full price by the number of tickets. Therefore, each person's share is $30 ÷ 4 = $7.50 per person when paying full price.