Higher June 2022 Paper 2 Q18
18 \(X = \dfrac{2a - b}{f}\)
| \(a = 7.5\) | correct to 1 decimal place. |
| \(b = 3.42\) | correct to 2 decimal places. |
| \(f = 2\) | correct to the nearest whole number. |
Work out the upper bound of the value of \(X\)
Show your working clearly.
(3)
| Scheme | Marks |
|---|---|
| 7.45, 7.55, 3.415, 3.425, 1.5, 2.5 | B1 |
| \((X =)\;\dfrac{2 \times 7.55 - 3.415}{1.5}\) oe eg \(\dfrac{11.685}{1.5}\) | M1 |
| Working required Answer: 7.79 | A1 |
| (3) | |
| (3 marks) |
Notes
B1: For one correct upper or one correct lower bound
Allow \(7.54\dot{9}\) for 7.55, \(3.424\dot{9}\) for 3.425, \(2.4\dot{9}\) for 2.5
M1: \(\dfrac{2 \times UB_a - LB_b}{LB_f}\) where \(7.5 \lt UB_a \leqslant 7.55\), \(3.415 \leqslant LB_b \lt 3.42\), \(1.5 \leqslant LB_f \lt 2\)
(also award this mark for \(\dfrac{7.55 - 3.415}{1.5}\) or \(\dfrac{2(7.55 - 3.415)}{1.5}\))
A1: must be from correct working