Higher June 2017 Paper 2 Q14
14 The graph shows the cost of some taxi journeys.
Work out a formula for \(C\) in terms of \(n\). [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| \(C = 0.6(0)n + 2.5(0)\) | B3 | oe Must have \(C =\) for B3 B2 \(C = 0.6n + k\ (k \ne 0)\) or \(C = an + 2.5\ (a \ne 0)\) or \(0.6n + 2.5\) B1 \(0.6n\) or \(an + 2.5\ (a \ne 0)\) or \(C = 60n + 250\) |
Additional guidance
| Allow correct fractions eg \(\dfrac{3}{5}\) or \(\dfrac{1}{1.\dot{6}}\) for 0.6 and/or \(\dfrac{5}{2}\) for 2.5 | |
| Allow \(0.6 \times n\) or \(n \times 0.6\) for \(0.6n\) eg \(C = 0.6 \times n + 2.5\) \(n \times 0.6 + 2.5\) \(0.6 \times n\) | B3 B2 B1 |
| Penalise by one mark the use of \(n0.6\) for \(0.6n\) eg \(C = n0.6 + 2.5\) \(n0.6 + 2.5\) \(n0.6\) | B2 B1 B0 |
| Penalise by one mark the use of different letters eg \(y = 0.6x + 2.5\) \(0.6x + 2.5\) \(2p + 2.5\) | B2 B1 B0 |
| Transposing 0.6 and 2.5 scores zero \(\;\) eg \(C = 2.5n + 0.6\) | B0 |
| Ignore £ signs \(\;\) eg £\(C =\) £\(0.6n +\) £2.5 or \(C =\) £\(0.60n +\) £2.5 | B3 |
| \(C = 1.2n + 2.5\) | B2 |
| \(1.2n + 2.5\) | B1 |
| \(C = 0.6n + 2.5\) in working with \(0.6n + 2.5\) on answer line | B3 |
| Equivalent formula but \(C\) not the subject scores B2 eg \(100C = 60n + 250\) | B2 |