Higher November 2023 Unit 2 Q15
15. The values \(b\) = 23, \(c\) = 0·73 and \(d\) = 8·3 are each given correct to 2 significant figures.
Use the formula
\[a = b - \frac{c}{d}\]to calculate the greatest possible value of \(a\).
Give your answer correct to 2 decimal places.
You must show all your working. [3]
| Scheme | Marks | Comments |
|---|---|---|
| \(23{\cdot}5 - \dfrac{0{\cdot}725}{8{\cdot}35}\) | M2 | If many attempts are offered without a method/answer being identified then mark final attempt. Accept 23·4999… or 8·34999… (or using recurring dot notation). Do not accept truncated values of 23·49 or 23·499 or 8·349 or 8·3499. Award M1 for correct use of values \(23 \lt b \leqslant 24\), \(0{\cdot}72 \leqslant c \lt 0{\cdot}73\) and \(8{\cdot}3 \lt d \leqslant 8{\cdot}4\) OR award M1 for correct use of 2 of the 3 correct limits. Allow sight of 23·413(…) for M2. |
| = 23·41 | A1 | Only award A1 if M2 gained. |