Higher June 2019 Paper 1 Q3
3 Find the highest common factor (HCF) of 72 and 90 (2)
| Answer | Mark | Mark scheme |
|---|---|---|
| 18 | M1 | for listing factors of 72 and 90, at least 4 correct for each (with no more than 1 incorrect in each list), could be in factor pairs OR for the prime factors of 72 (2, 2, 2, 3, 3) or 90 (2, 3, 3, 5) |
| A1 | for 18 or \(2 \times 3^2\) oe | |
| SC B1 for answer of 6 or 9 if M0 scored |
Additional guidance
Factors of 72: 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72
Factors of 90: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90
2, \(3^2\) is not enough, it must be a product