Foundation January 2019 Paper 2R Q13
13
(a) Solve \(7x + 3 = x - 18\) (2)
(b) Make \(w\) the subject of \(t = 7w + 3\) (2)
Pencils cost 2 dollars each.
Rulers cost 3 dollars each.
Edith buys \(p\) pencils and \(r\) rulers.
The total cost is \(T\) dollars.
(c) Write down a formula for \(T\) in terms of \(p\) and \(r\). (3)
| Scheme | Marks |
|---|---|
| \(7x - x = -18 - 3\) \((6x = -21)\) oe | M1 |
| −3.5 | A1 |
| (2) |
Notes
M1: Collect terms in ‘\(x\)’ on one side and number terms on the other.
| Scheme | Marks |
|---|---|
| \(7w = t - 3\) oe | M1 |
| \(w = \dfrac{t - 3}{7}\) | A1 |
| (2) |
Notes
M1: Isolating term in \(w\)
A1: Must have \(w\) =
| Scheme | Marks |
|---|---|
| \(T = 2p + 3r\) | B3 |
| (3) | |
| (7 marks) |
Notes
B3: For \(T = 2p + 3r\) oe
(B2 for \(2p + 3r\) or \(T = 3p + r\) or \(T = p + 2r\) or \(T = 3p + 2r\))
(B1 for \(2p + r\) or \(p + 3r\) or \(3p + 2r\) or or \(3p + r\) or \(p + 2r\))