Foundation November 2024 Paper 3 Q26
26
| Volume of a sphere \(= \dfrac{4}{3} \times \pi \times r^3\) where \(r\) is the radius |
Ria works out the volume of this hemisphere in terms of \(\pi\)
Here is her work.
\[\text{Volume of a hemisphere} = \dfrac{4}{3} \times 7.5 \times 3 \div 2 = 15\]Write down two mistakes she has made. [2 marks]
| Answer | Mark | Comments |
|---|---|---|
Any two of the following statements
| B2 | oe B1 for one correct statement |
Additional guidance
| Ignore irrelevant statements for B1 or B2 | |
| Ignore incorrect statements or incorrect values with correct reasons, unless contradictory, for B1 | |
| Need to do \(\pi \times 7.5^3\) (calculation shows 2 mistakes) | B2 |
| The answer should be \(281.25\pi\) (doesn’t show mistakes but a correct answer in terms of \(\pi\)) | B1 |
| Need to do \(\pi \times 7.5^3\) to get 883.6 (883.6 is not an answer in terms of \(\pi\)) | B1 |
| The answer should be [883.5, 884] | B0 |
| 15 is wrong | B0 |
| Statements about not using \(\pi\) in the calculation She hasn’t multiplied by \(\pi\) / pi Used 3 for \(\pi\) Hasn’t used 3.14 The answer is not in terms of \(\pi\) It is not in terms of \(\pi\) | B1 B1 B0 B0 B0 |
| Statements about not cubing 7.5 She should have done \(7.5^3\) She hasn’t cubed the radius She multiplied it by 3 Hasn’t cubed a number | B1 B1 B1 B0 |
| Statements about no units She hasn’t given any units She should have written cm\(^3\) | B1 B1 |