Final answer:
The total cost for 3 people to go to the water park including the registration fee would be $48.50, determined by the equation C = 14.50p + 5, where p is the number of people.
Step-by-step explanation:
To represent the total cost of going to the water park for 3 people, you can set up a linear equation based on the given information. The equation would include a one-time registration fee and the cost per person. Therefore, the equation to determine the total cost (C) for p people is given by:
C = 14.50p + 5
Substitute the number of people (p = 3) into the equation to calculate the total cost for 3 people:
C = 14.50(3) + 5
C = 43.50 + 5
C = $48.50
The cost for 3 people to go to the water park would be $48.50.