Foundation November 2020 Paper 2 Q18
18 Kim buys pet food in 1.5 kg packs.
Her pet needs 0.8 kg of food each week.
She wants to have enough food for the next 14 weeks.
She already has two 1.5 kg packs.
Work out the smallest number of packs she needs to buy.
You must show your working. [4 marks]
| Answer | Mark | Comments |
|---|---|---|
| Alternative method 1 | ||
| \(14 \times 0.8\) or 11.2 or \(1.5 \times 2 \div 0.8\) or 3.75 | M1 | oe implied by 8.2 or 5.4(6…) or 5.47 or 5.5 |
| their \(11.2 - 2 \times 1.5\) or their \(11.2 - 3\) or 8.2 or \((14 -\) their \(3.75) \times 0.8\) or 8.2 | M1dep | oe implied by 5.4(6…) or 5.47 or 5.5 |
| their \(8.2 \div 1.5\) or 5.4(6…) or 5.47 or 5.5 or \(5 \to 7.5\) or \(6 \to 9\) with M2 seen | M1dep | oe |
| 6 with 5.4(6…) or 5.47 or 5.5 seen or 6 with \(5 \to 7.5\) and \(6 \to 9\) and M2 seen | A1 | |
| Alternative method 2 | ||
| \(14 \times 0.8\) or 11.2 | M1 | oe implied by 7.4(6…) or 7.47 or 7.5 (packs) |
| their \(11.2 \div 1.5\) or 7.4(6…) or 7.47 or 7.5 (packs) or \(7 \to 10.5\) or \(8 \to 12\) with M1 seen | M1dep | oe \(\dfrac{14 \times 0.8}{1.5}\) is M2 |
| their \(7.4(6…) - 2\) or 5.4(6…) or 5.47 or 5.5 or \(7 - 2\) or \(8 - 2\) with M2 seen | M1dep | oe |
| 6 with 7.4(6…) or 7.47 or 7.5 seen or 6 with \(7 \to 10.5\) and \(8 \to 12\) and M2 seen | A1 | |
| Alternative method 3 Working in weeks | ||
| \(1.5 \div 0.8\) or 1.875 | M1 | oe implied by 7.4(6…) or 7.47 or 7.5 (packs) |
| \(14 \div\) their 1.875 or 7.4(6…) or 7.47 or 7.5 (packs) or \(7 \to 13.1(25)\) or \(8 \to 15\) | M1dep | oe |
| their \(7.4(6…) - 2\) or 5.4(6…) or 5.47 or 5.5 or \(7 - 2\) or \(8 - 2\) with M2 seen | M1dep | oe |
| 6 with 7.4(6…) or 7.47 or 7.5 seen or 6 with \(7 \to 13.1(25)\) and \(8 \to 15\) seen | A1 | |
Additional guidance
Select the scheme that favours the student for the first 2 M marks even if not subsequently used
Alts 2 and 3 the 7.5 must be packs not 7.5 kg (from \(5 \times 1.5\))
For the final mark of Alt 1, eg \(5 \to 7.5\) and 0.7 (short) is sufficient evidence and there are equivalents for Alts 2 and 3
For the final mark of Alt 1, eg \(6 \to 9\) and 0.8 (over) is sufficient evidence and there are equivalents for Alts 2 and 3
Accept repeated addition or subtraction of 1.5 if clear
eg \(1.5 + 1.5 + 1.5 + 1.5 + 1.5 = 7.5\) implies \(5 \to 7.5\)