Foundation November 2017 Paper 3 Q8
8 The average mass of a man is 84 kg and of a woman is 70 kg.
A lift can safely carry 630 kg.
To find how many people the lift can safely carry, Dan divides the safe total mass by the average mass of a person.
\[630 \div 77 = 8.18\ldots\](a) How has the average mass of a person, 77 kg, been worked out? [1]
Dan decides that his answer shows the lift can safely carry 8 people.
(b) Explain why he is wrong and give an example, with working, to support your answer. [3]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| (Men’s average + women’s average) \(\div\) 2 oe | 1 | Accept half way between the two masses/averages oe or (84 + 70) \(\div\) 2 oe or (84 – 70) \(\div\) 2 + 70 oe | Allow half way between them or midpoint or added the two and halved May be in stages. Condone missing brackets |
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| Correct reason involving distribution of men/women or not all average | 1 | Saying he is correct scores 0 for reason mark but may score example marks Some may be overweight 8 men [0 women] 7 men 1 woman 6 men and 2 women | Can carry 9 women is not enough May be a combination of both 8 \(\times\) 84 = 672 7 \(\times\) 84 + 1 \(\times\) 70 = 658 6 \(\times\) 84 + 2 \(\times\) 70 = 644 |
| Correct example supporting their reason with result \(\geqslant\) 630 | 2 | M1 for correct calculation supporting their reason wrongly evaluated or correct value \(\geqslant\) 630 supporting their reason for their example without working or A correct calculation involving a mass and a number of people. | Eg 8 men weigh 672 kg Multiplication or division Eg 84 \(\times\) 8 = 672 or 630 \(\div\) 84 = 7.5 or 630 \(\div\) 70 = 9 |