Standard difficulty · 20 questions · 40 marks
Show your working for Sections B and C. Answers are on the last page — try every question first!
Permutations and Combinations · AW-11M-PNC-2026-V1 · For parents — fold back or tear off before handing the sheet to your child.
| Q | Answer | Working |
|---|---|---|
| 1 | (d) 120 | 6 × 5 × 4 |
| 2 | (c) 3,003 | 15! ÷ (5! × 10!) |
| 3 | (d) 34,650 | 11! ÷ (repeats: I × 4, S × 4, P × 2) |
| 4 | (a) 42 | 7P2 |
| 5 | (a) 1 | — |
| 6 | (d) 150 | 6C2 × 5C3 |
| 7 | (a) 30 | 6 × 5 |
| 8 | (a) Both A and R are true, and R is the correct explanation of A. | A is true: 8C3 = 56 and 8C5 = 56. R is true and explains A. |
| 9 | 720; 120 | 6!; fix O, then 5! |
| 10 | 90 | units digit: 3 even choices; the rest: 6P2 |
| 11 | n = 18 | n(n − 1) = 306 |
| 12 | 1,295 | all committees 15C4 minus all-men 8C4 |
| 13 | 240 | treat NG as one block: 5! × 2! |
| 14 | n = 16; 16C2 = 120 | ⁿCᵣ = ⁿCₛ with r ≠ s means r + s = n |
| 15 | 136 | 17C2 |
| 16 | Lines: 31; triangles: 100 | 10C2 − 6C2 + 1; 10C3 − 6C3 |
| 17 | (a) 180; (b) 36 | (b) treat the vowels OAO as one block: 12 arrangements of the block and the consonants, × 3 arrangements of the vowels inside it |
| 18 | 1,582 | 2 girls: 8C2 × 9C2 = 1,008; 3 girls: 8C3 × 9C1 = 504; 4 girls: 8C4 × 9C0 = 70 |
| 19 | 22,100; (a) 4,512; (b) 4,804 | 52C3; 4C1 × 48C2; 52C3 − 48C3 (hands with no ace) |
| 20 | (a) 6,227,020,800; (b) 3,628,800; (c) 29,030,400 | (b) 7! × 6!; (c) girls as one block: 8! × 6! |