Higher November 2021 Paper 2 Q2
2
(a) Find the Highest Common Factor (HCF) of 60 and 84 (2)
(b) Find the Lowest Common Multiple (LCM) of 24 and 40 (2)
| Answer | Mark | Mark scheme |
|---|---|---|
| 12 | M1 | for a correct factor tree for either 60 or 84 with no more than one arithmetic error or for listing factors of 60 or 84, at least 4 correct for either (with no more than 1 incorrect in either list), could be in factor pairs or for the prime factors of 60 (2, 2, 3, 5) or 84 (2, 2, 3, 7) |
| A1 | for 12 or \(2 \times 2 \times 3\) oe SC B1 for answer of 4 or 6, if M0 scored |
Additional guidance
Condone the use of 1 in any factor tree
60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60
84: 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84
2,2,3 is not enough, it must be a product
| Answer | Mark | Mark scheme |
|---|---|---|
| 120 | M1 | for a correct factor tree for either 24 or 40 with no more than one arithmetic error or for at least 3 multiples of both 24 and 40 (can include 24 and 40) or for the prime factors of either 24 (2, 2, 2, 3) or 40 (2, 2, 2, 5) or for a common multiple from their lists (\(\neq 120\)) |
| A1 | for 120 or \(2 \times 2 \times 2 \times 3 \times 5\) oe |
Additional guidance
Condone the use of 1 in any factor tree
24: 24, 48, 72, 96, 120, …
40: 40, 80, 120, …
For the list not containing 120, accept the first 3 correct multiples or one error in the first 4 multiples