Question

What key do I need to use??

Answer 1

First, I would say shade your boxes, and then each shaded box is equal to 1 person. So your answer would be 1 person.
Or you could put 1 shaded box into the movies box, 2 shaded boxes into the sports box, and don't add any into the cartoon box, and then each shaded box would be equal to 3 persons.
I hope this helps, if you need any further help on this problem, just ask.