1. **Stating the problem:** We have 5 class prefects: Eimear (E), Samantha (S), Mia (M) who are girls, and Paul (P), Neil (N) who are boys. We need to find all possible pairs of one boy and one girl supervising together, either in the morning or afternoon. 2. **Understanding the requirement:** Each pair must consist of one boy and one girl. 3. **Listing the girls and boys:** Girls = \{E, S, M\}, Boys = \{P, N\}. 4. **Forming pairs:** Each girl can pair with each boy. 5. **All possible pairs:** - E with P - E with N - S with P - S with N - M with P - M with N 6. **Tree diagram structure:** - Start with girls as the first branch. - From each girl, branch out to each boy. 7. **Final list of combinations:** $$\{(E,P), (E,N), (S,P), (S,N), (M,P), (M,N)\}$$ This completes the listing of all possible boy-girl pairs supervising together.