A boy with a camera comes along and takes a boy-girl shot.
What is the minimum number of people that could have been on the viewing platform when the photo was taken?
The people mentioned in the question are the girl working at the stall, the boy with the camera, and the girl and boy in the picture.
You can take a picture without having to hold the camera.
You need to figure out the minimum number of people present, so try to work out if any of the people mentioned could possibly double up.
The boy with the camera took a picture with himself in.
He took a 'boy-girl' shot, so there needs to be a girl in the picture with him.
Answer for 'Picture the Scene'
The answer is '2'.