Higher November 2019 Paper 3 Q11
11 Work out
cube root of 512 : reciprocal of 0.4
Give your answer in the form \(\quad n : 1\) [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| 8 | B1 | |
| \(\dfrac{1}{0.4}\) or \(\dfrac{10}{4}\) or 2.5 or \(\dfrac{1}{\,\dfrac{2}{5}\,}\) or \(\dfrac{5}{2}\) or \(2\dfrac{1}{2}\) | M1 | \(8 \times 0.4\) or 3.2 implies B1M1 16 : 5 or equivalent ratio implies B1M1 |
| 3.2 : 1 or \(\dfrac{16}{5} : 1\) or \(3\dfrac{1}{5} : 1\) | A1ft | ft B0M1 |
Additional guidance
| \(8^3 = 512\) or \(8 \times 8 \times 8 = 512\) alone is not sufficient for B1 | |
| ft answers must have \(n\) exact or correctly rounded to at least 2 sf eg \(\sqrt{512} = 22.62\) (incorrect and truncated) 2.5 9.05 : 1 | B0 M1 A1ft |
| ft answer exact surd value eg \(\sqrt{512} = 16\sqrt{2}\) 2.5 9.05 : 1 or \(\dfrac{32}{5}\sqrt{2} : 1\) | B0 M1 A1ft |