4MA0 Foundation January 2016 Paper 1 Q12
12 Here is a number machine.
| input | → | multiply by 4 | → | subtract 7 | → | output |
(a) Work out the input when the output is 17 (2)
(b) Find an expression, in terms of \(x\), for the output when the input is \(x\). (2)
| Scheme | Marks |
|---|---|
| (17 + 7) ÷ 4 or 24 ÷ 4 | M1 |
| 6 | A1 |
| (2) |
Notes
M1: accept 17 + 7 ÷ 4
| Scheme | Marks |
|---|---|
| \(4x - 7\) | B2 |
| (2) |
Notes
B2: B1 for \(4x\) or \(4 \times x\)
NB: \(x = 4x - 7\) scores B1 only