Foundation November 2017 Paper 3 Q23
23 Show that 268 can be written as the sum of a power of 3 and a square number. [2 marks]
| Answer | Mark | Comments |
|---|---|---|
| Lists three from 3, 9, 27, 81, 243, 729 or lists three from 1, 4, 9, 16, …, 225, 256, 289 or correctly evaluating a power of 3 + a square number or correctly evaluating 268 – a power of 3 or correctly evaluating 268 – a square number | M1 | eg 27 + 25 = 52 or \(3^3 + 5^2 = 52\) eg 268 – 27 = 241 eg 268 – 49 = 219 |
| 243 + 25 or \(3^5 + 5^2\) | A1 | oe Addition sign must be seen in working or on answer line |
Additional guidance
| \(3^5\), \(5^2\) or \(3^5\) and \(5^2\) on answer line | M1A0 |
| 268 – 243 = 25 | M1A0 |
| 243, 25 or 243 and 25 on answer line | M1A0 |
| Beware of \(5^3 + 5^2\) |