10 questions · Form 5 Additional Mathematics Bab 4: Permutation and Combination
10 questions · plays in fullscreen
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. Calculate the value of ⁶P₃.
Answer: A
⁶P₃ = 6! / (6 - 3)! = 6! / 3! = 6 × 5 × 4 = 120.
2. Find the value of n if ⁿP₂ = 42.
Answer: A
ⁿP₂ = n(n - 1) = 42 => n² - n - 42 = 0 => (n - 7)(n + 6) = 0. Since n must be positive, n = 7.
3. If ⁿC₃ = ⁿC₅, find the value of n.
Answer: A
Using property ⁿC_r = ⁿC_(n-r): n - 3 = 5 => n = 8.
4. A box contains 5 red balls and 4 blue balls. How many ways can 3 balls be selected such that at least 2 red balls are chosen?
Answer: A
Case 1: 2 red, 1 blue = ⁵C₂ × ⁴C₁ = 10 × 4 = 40. Case 2: 3 red, 0 blue = ⁵C₃ × ⁴C₀ = 10 × 1 = 10. Total ways = 40 + 10 = 50.
5. Find the number of ways to arrange 5 distinct beads on a necklace.
Answer: A
For a necklace where clockwise and counter-clockwise arrangements are identical: (n - 1)! / 2 = (5 - 1)! / 2 = 242 = 12.
6. A test paper consists of 10 questions divided into Section A (5 questions) and Section B (5 questions). A candidate needs to answer 6 questions, selecting at least 2 from each section. How many different selections can be made?
Answer: A
Possible distributions (Sec A, Sec B): (2, 4) = ⁵C₂ × ⁵C₄ = 10 × 5 = 50. (3, 3) = ⁵C₃ × ⁵C₃ = 10 × 10 = 100. (4, 2) = ⁵C₄ × ⁵C₂ = 5 × 10 = 50. Total = 50 + 100 + 50 = 200.
7. How many triangles can be formed using the vertices of an octagon?
Answer: A
An octagon has 8 vertices. Choosing 3 vertices forms a triangle: ⁸C₃ = 8 × 7 × 63 × 2 × 1 = 56.
8. Find the number of ways to arrange 6 people around a circular table.
Answer: A
Circular permutation = (n - 1)! = (6 - 1)! = 5! = 120.
9. In how many ways can a committee of 4 people be selected from 6 men and 5 women if the committee must consist of 2 men and 2 women?
Answer: A
Ways to choose 2 men from 6 = ⁶C₂ = 15. Ways to choose 2 women from 5 = ⁵C₂ = 10. Total ways = 15 × 10 = 150.
10. Evaluate ⁴P₄ + ⁴C₄.
Answer: A
⁴P₄ = 4! = 24. ⁴C₄ = 1. Total = 24 + 1 = 25.