Higher November 2021 Paper 6 Q18
18 Rearrange this formula to make \(y\) the subject.
\[\frac{5y + 2}{y} = \frac{3t - 7}{2}\][5]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| \(y = \dfrac{4}{3t - 17}\) or \(y = \dfrac{-4}{17 - 3t}\) | 5 | B4 for \(\dfrac{4}{3t - 17}\) or \(y = \dfrac{2}{1.5t - 8.5}\) as final answer OR M2 for \(10y + 4 = 3ty - 7y\) or \(5 + \dfrac{2}{y} = 1.5t - 3.5\) or M1 for \(\dfrac{2(5y + 2)}{y} = 3t - 7\) or \(5y + 2 = \dfrac{y(3t - 7)}{2}\) or \(10y + 4\) or \(3ty - 7y\) seen or \(5 + \dfrac{2}{y} = \dfrac{3t - 7}{2}\) or \(\dfrac{5y + 2}{y} = 1.5t - 3.5\) | To award full marks, solution must be correct |
| M1ft for correctly collecting \(y\) terms on one side and non-\(y\) terms on the other (need not be simplified at this stage) | eg \(4 = 3ty - 7y - 10y\) or \(\dfrac{2}{y} = 1.5t - 3.5 - 5\) ft for formulae of equal difficulty (eg must include a \(ty\) term oe) | ||
| M1ft for factorising their 2 or 3 terms | eg \(4 = y(3t - 17)\) or \(\dfrac{y}{2} = \dfrac{1}{1.5t - 8.5}\) | ||