Higher November 2020 Paper 3 Q18
18 The pressure in a tyre is 30 pounds per square inch.
Convert the pressure into kilograms per square centimetre. [3 marks]
| Use 1 pound = 0.45 kilograms and 1 inch = 2.54 centimetres |
| Answer | Mark | Comments |
|---|---|---|
| Alternative method 1 | ||
| \(30 \times 0.45\) or 13.5 | M1 | |
| their \(13.5 \div 2.54^2\) | M1dep | oe eg \(\dfrac{30 \times 0.45}{2.54^2}\) |
| 2.09(2…) or 2.093 or 2.1 | A1 | SC1 5.31(4…) or 5.315 or 5.3 |
| Alternative method 2 | ||
| \(30 \div 2.54^2\) or 4.65(0…) | M1 | oe |
| their \(4.65(0\ldots) \times 0.45\) | M1dep | oe eg \(\dfrac{30}{2.54^2} \times 0.45\) |
| 2.09(2…) or 2.093 or 2.1 | A1 | SC1 5.31(4…) or 5.315 or 5.3 |
| Alternative method 3 | ||
| \(0.45 \div 2.54^2\) or 0.0697(5…) or 0.0698 | M1 | oe |
| their \(0.0697(5\ldots) \times 30\) | M1dep | oe eg \(\dfrac{0.45}{2.54^2} \times 30\) |
| 2.09(2…) or 2.093 or 2.1 | A1 | SC1 5.31(4…) or 5.315 or 5.3 |
Additional guidance
SC1 when 2.54 is used and not \(2.54^2\)