Higher November 2018 Unit 1 Q9
9. A cuboid has sides \(x\) cm, 5 cm and 7 cm.
The total surface area of the cuboid is 142 cm2.
Form an equation in terms of \(x\).
Solve the equation to find \(x\). [4]
| Scheme | Marks | Comments |
|---|---|---|
| Sight of at least two correct different surface areas. | B1 | Sight of two of 35(cm2), \(5x\)(cm2), \(7x\)(cm2). |
| \(2 \times (35 + 5x + 7x) = 142\) or equivalent | M2 | Allow M1 for ‘sum of at least 3 correct surface areas = 142’. |
| \(x = 3\) | A1 | C.A.O. If M0, allow SC1 for x = 3 with no prior equation shown. |