Chapter 2 Practice Paper: Linear Inequalities — mark scheme
Secondary 2 · Lower Secondary Mathematics (G2 / G3)
Mark scheme
Linear Inequalities
Chapter 2 Practice Paper · Maximum mark: 30
Notes for markers
- Award one mark for each point marked [1], up to the marks shown for the part.
- Accept answers worded differently that show the same understanding.
- Units are required where the answer line shows one. ecf: allow an error carried forward.
Section A: Multiple-choice questions[10 marks]
| Question | Answer | |
|---|---|---|
| 1 | BThe bar under the sign is the “or equal to” part. | 1 |
| 2 | CThe open circle excludes −1 and the rightward shading takes the larger values. | 1 |
| 3 | AAdding 6 to both sides gives x ≥ 10; adding never flips the sign. | 1 |
| 4 | DDividing by the positive 5 keeps the sign: x < 9. | 1 |
| 5 | BDividing by −4 flips ≤ into ≥, giving x ≥ −3. | 1 |
| 6 | C−x < −2, and dividing by −1 flips the sign: x > 2. | 1 |
| 7 | A4 is below the boundary; 4.5 is excluded and is not an integer anyway. | 1 |
| 8 | DThe integers are −1, 0, 1, 2, 3 — five of them. | 1 |
| 9 | B“At most” allows exactly 6, so t ≤ 6. | 1 |
| 10 | CSubtract 5 to get 2x ≤ 12, then divide by 2: x ≤ 6. | 1 |
Section B: Structured questions[20 marks]
| Question | Answer and marking points | Marks |
|---|---|---|
| 1(a) | 4x < 16, so x < 4.
| 2 |
| 1(b) | An open circle at 4, with shading to the left.
| 1 |
| 1(c) | 3 (the integer just below the open boundary 4). [1] | 1 |
| 1(d) | No: 4(4) − 3 = 13, and 13 is not less than 13; the boundary is open.
| 1 |
| Total for Question 1 | 5 | |
| 2(a) | −3x ≥ −6; dividing by −3 and flipping gives x ≤ 2.
| 3 |
| 2(b) | The flip happened when dividing by −3; dividing by a negative number reverses which side is bigger, so the comparison must reverse.
| 2 |
| Total for Question 2 | 5 | |
| 3(a) | −2, −1, 0, 1, 2, 3, 4.
| 2 |
| 3(b) | 4 (the closed boundary itself is a solution). [1] | 1 |
| 3(c) | Four: 1, 2, 3, 4.
| 2 |
| Total for Question 3 | 5 | |
| 4(a) | 120 + 6c ≤ 300.
| 2 |
| 4(b) | 6c ≤ 180, so c ≤ 30.
| 2 |
| 4(c) | 30 chairs [1] | 1 |
| Total for Question 4 | 5 |
— End of mark scheme —