Higher November 2021 Paper 1 Q13
13 Ted is trying to change \(0.\dot{4}\dot{3}\) to a fraction.
Here is the start of his method.
\(x = 0.\dot{4}\dot{3}\)
\(10x = 4.\dot{3}\dot{4}\)
\(10x - x = 4.\dot{3}\dot{4} - 0.\dot{4}\dot{3}\)
Evaluate Ted’s method so far. (1)
| Answer | Mark | Mark scheme |
|---|---|---|
| Explanation | C1 | explanation Acceptable examples he should have used \(100(x)\) rather than \(10(x)\) he should have used \(1000x\) and \(10x\) Ted’s working does not eliminate the recurring decimals the recurring numbers after the decimal point have to be in the same sequence he should have multiplied by 100 to subtract easier after the decimal point he should have multiplied by 100 because two numbers are recurring Not acceptable examples it is not correct the method is not complete he should have used \(1000x\) he should have multiplied by 100 he should have multiplied by 100 and then done \(100x - 10x\) to give 43/90 |