He has a choice of three colours of shirt and a choice of three styles of tie.
List all the possible combinations Harris can choose.
Home > Maths quizzes > Grade 6 Quizzes > The product rule
Grade 6 • 6C • 10 Questions (31 Marks)
Explanation:
The product rule for counting states that if there are m ways to make a first choice and n ways to make a second choice, the total number of combinations is m × n.
If items cannot be repeated, reduce the number of available choices by 1 for each next position. If you are choosing a pair of items where order does not matter (e.g. picking a team of 2 people or handshakes), divide by 2 at the end so each pair is not counted twice.
Example 1: A restaurant menu has 5 starters, 8 main courses, and 4 desserts. How many different 3-course meals can be chosen?
Solution:
Example 2: A 4-digit PIN uses digits from 1 to 9 with no repeated digits. The first digit must be even (2, 4, 6 or 8). How many PINs are possible?
Solution: