Foundation November 2019 Paper 2 Q21
21 \(a\) and \(b\) are both prime numbers.
They are each less than 20
Give an example where \(\quad a + b \quad\) is odd but not prime. [2 marks]
| Answer | Mark | Comments |
|---|---|---|
| 2 and 7 or 2 and 13 or 2 and 19 | B2 | either order B1 any pair of different numbers chosen from 2, 3, 5, 7, 11, 13, 17, 19 eg 2 and 3 or 3 and 5 |
Additional guidance
| Mark the answer line but, if answer line blank, the pair of numbers must be clearly selected for B2 or B1 | |
| List of prime numbers without selecting a pair | B0 |