Foundation June 2022 Paper 2 Q15
15 \(y\) is inversely proportional to \(x\).
\(y = 20\) when \(x = 3\).
Find the value of \(y\) when \(x = 12\). [3]
| Answer | Marks | Part marks and guidance | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 5 | 3 | B1 for \(y = \dfrac{k}{x}\) oe soi by \(20 = \dfrac{k}{3}\) or \(k = 60\) M1 for [\(y =\)] \(\dfrac{\textit{their}\ k}{12}\) | e.g. for 2 marks \(\dfrac{60}{12}\) oe | ||||||||||||
| OR M2 for \(20 \times 3 = y \times 12\) or better or M1 for \(20 \times 3\) | Implied by 60 | ||||||||||||||
| Alternative method: M2 for \(20 \div (12 \div 3)\) or M1 for \(12 \div 3\) If 0 scored SC1 for answer of 80 | May be seen in a table: M2 for \(\times 4\) oe and \(\div 4\) oe or M1 for \(\times 4\) oe
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