Higher November 2021 Paper 5 Q3
3 A car mechanic has a tin containing 5 litres of engine oil.
Each week they use 450 millilitres of this oil for their vehicles.
The car mechanic says
After 9 weeks I will have used over 80% of the oil in this tin.
Are they correct?
Show how you decide. [5]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| 5000 [ml] or 0.45 [L] soi | B1 | Correct conversion at any stage | |
| 9 × 450 oe | M1 | Alternate approaches are possible | |
| Correct attempt to find 80% or 20% of 5000 oe | M1 | or \(\dfrac{9 \times 450}{5000}\)[×100] oe or \(\dfrac{5000 - 9 \times 450}{5000}\)[×100] oe | M1 may be implied by 4000 or 1000 or 81% or 19% seen |
| 4050 and 4000 or 950 and 1000 and [They are] correct oe | A2 | or 81% [and 80%] or 19% [and 20%] After A0 scored B1 for 4050 or 4000 or 950 or 1000 | For A2 accept in other correct consistent units for comparison e.g. 4.05[L] and 4[L] and must have no incorrect statement For B1 accept e.g. 4.05[L] or 4[L] |