Intermediate November 2018 Unit 1 Q18
18. 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 × ( 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. |