Final answer:
The correct equation to find the number of people p for which the cost of a waterpark and a rock-climbing gym is the same is 40p + 5p = 150 + 20p.
Step-by-step explanation:
To determine the number of people p for which the cost of going to the waterpark and the rock-climbing gym would be the same, we need to set up an equation where both costs are equal. The waterpark costs $40 per person for admission and $5 per person for tube rentals. Therefore, the total cost for the waterpark would be 40p + 5p. The rock-climbing gym has a flat facility rental fee of $150 and an additional $20 per person. So, the total cost for the rock-climbing gym is 150 + 20p. Setting these two expressions equal to each other, we get: 40p + 5p = 150 + 20p. Solving for p will give us the number of people needed for the costs to be equal.