Higher November 2021 Paper 6 Q14
14 \(y\) is inversely proportional to the square root of \(x\).
\(y = 5\) when \(x = 36\).
(a) Find a formula linking \(x\) and \(y\). [3]
(b) Find the value of \(x\) when \(y = 20\). [3]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| \(y = \dfrac{30}{\sqrt{x}}\) oe | 3 | M1 for \(y = \dfrac{k}{\sqrt{x}}\) oe B1 for [\(k =\)] 30 | eg condone \(y = \dfrac{k}{\sqrt{36}}\) for M1 |
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| 2.25 oe | 3 | B2 for \(\sqrt{x} = \dfrac{3}{2}\) oe or M1 for \(20 = \dfrac{\textit{their } 30}{\sqrt{x}}\) or \(\dfrac{20}{5} = \dfrac{\sqrt{36}}{\sqrt{x}}\) | |