Foundation November 2020 Paper 1 Q17
17 Here is a list of six numbers written in order of size.
4 7 \(x\) 10 \(y\) \(y\)
The numbers have
a median of 9
a mean of 11
Find the value of \(x\) and the value of \(y\).
(4)
| Scheme | Marks |
|---|---|
| \(\dfrac{x + 10}{2} = 9\) or \(x = 8\) | M1 |
\(\dfrac{4 + 7 + x + 10 + y + y}{6} = 11\) oe or ‘66’ – 4 – 7 – 10 (= 45) | M1 |
| (\(y\) =) (6 × 11 – 4 – 7 – 10 – ‘8’) ÷ 2 | M1 |
| \(x = 8\) and \(y = 18.5\) oe | A1 |
| (4) | |
| (4 marks) |
Notes
M1: (indep)
M1: where \(x\) may be a number \(7 \lt x \lt 10\)
M1: ft their value of \(x\) provided \(7 \lt x \lt 10\) for a fully correct method