Foundation June 2019 Paper 3 Q14
14 Joan makes cups of tea and coffee at a lunch club.
Each cup requires 250 ml of boiling water.
She has a kettle that boils up to 1.7 litres of water each time.
She boils 10 litres of water in an urn.
She then uses the kettle to boil the rest of the water she needs.
Find the least number of times that Joan needs to boil the kettle to make 56 cups.
Show how you decide. [5]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| 3 with correct full method | 5 | B4 for 2.3 to 2.4 as final answer or B3 for figs 23 to 24 final answer OR B1 for correct unit conversion of a value at some stage (not just 1000ml = 1 litre) M1 for \(56 \times 250\) soi 14 000 M1 for their 14 000 – their 10 000 soi 4 000 M1 for \(\dfrac{\text{their } 14\,000 - \text{their } 10\,000}{\text{their } 1700}\) oe soi 2.35... ALTERNATIVE METHOD M1 for \(10\,000 \div 250\) or \(10 \div 0.25\) soi 40 [cups] M1 for 56 – their 40 soi 16 M1 for \(1700 \div 250\) or \(1.7 \div 0.25\) soi 6.8 [cups] or 6 cups 200 ml or 6 or 7 M1 for their 16 ÷ their 6.8 oe soi 2.3 to 2.4 | B4 and B3 Must be sure this is number of kettles oe and not a faulty unit conversion Conversion may be implied by values of consistent order eg \(56 \times .25\) or 14 000 – 10 000 or \(56 \times [0].25\) soi 14 or their 14 – 10 soi 4 or \(\dfrac{\text{their } 14 - \text{their } 10}{1.7}\) Use of kettle only B4 for answer 9 or B3 for 8.2 to 8.3 or B2 for figs 82 to 83 OR B1 for correct unit conversion at some stage AND M1 for \(56 \times 250\) soi 14 000 M1 for \(\dfrac{\text{their } 14\,000}{\text{their } 1700}\) oe OR M1 for \(1700 \div 250\) or \(1.7 \div 0.25\) soi 6.8 [cups] or 6 cups 200 ml or 6 or 7 M1 for 56 ÷ their 6.8 oe |