Combinations Games 811Da7
1. **Problem statement:** Helen wants to choose one main course and one dessert from 6 main courses and 8 desserts.
2. **Formula for combinations:** When choosing one item from each of two categories, the total number of combinations is the product of the number of choices in each category.
3. **Explanation:** Since Helen must pick one main course and one dessert, multiply the number of main courses by the number of desserts.
4. **Intermediate work:** Total combinations = $6 \times 8$
5. **Problem statement:** In a rugby tournament with 10 teams, each team plays every other team exactly once.
6. **Formula for total games:** The total number of games is the number of unique pairs of teams, which is given by the combination formula $\binom{n}{2} = \frac{n(n-1)}{2}$ where $n$ is the number of teams.
7. **Explanation:** Each game is played between two different teams, so count all unique pairs.
8. **Intermediate work:** Total games = $\frac{10 \times 9}{2}$
This method helps you find the number of combinations and total games without directly giving the final numbers.