The hidden question here is "What is the total cost of admission for all members and adults on the trip?"
To find the total cost (c), we first determine how many people went on the trip:
- There are 17 members in the scout troop.
- There are also 4 adults on the trip.
Total number of people = 17 (members) + 4 (adults) = 21 people.
Next, we calculate the total cost:
Total cost, \( c = \) Total number of people × Admission cost per person \[ c = 21 \times 3 = 63. \]
Therefore, the total cost is \( c = 63 \).
The correct response from the choices provided is:
"How many people went on the trip? c = $63."