There are 17 members in the scout troop. All of the members went on a trip to a state park. There were also 4 adults on the trip. What was the total cost, c, if the admission for each person was $3?
What is the hidden question and the solution?
 A. 
How many people went on the trip? c = $39
 B. 
How many people went on the trip? c = $63
 C. 
How many adults went on the trip? c = $12
 D. 
How many adults went on the trip? c = $63