Foundation January 2020 Paper 1 Q15
15
(a) Find the highest common factor (HCF) of 28 and 70 (2)
(b) Find the lowest common multiple (LCM) of 28 and 105 (2)
| Scheme | Marks |
|---|---|
| 1, 2, 4, 7, 14, 28 and 1, 2, 5, 7, 10, 14, 35, 70 or 2 × 2 × 7 and 2 × 5 × 7 or  | M1 |
| 14 | A1 |
| (2) |
Notes
M1: for starting to list at least four factors of each number
or 2, 2, 7 and 2, 5, 7 seen (may be in a factor tree and ignore 1)
or a fully correct Venn diagram
A1: cao
| Scheme | Marks |
|---|---|
28, 56, 84, 112… and 105, 210, 315, 420… or 2, 2, 7 and 3, 5, 7 or  | M1 |
| 420 | A1 |
| (2) | |
| (4 marks) |
Notes
M1: for any correct valid method e.g.
for starting to list at least four multiples of each number
or 2, 2, 7 and 3, 5, 7 seen (may be in a factor tree and ignore 1)
or a fully correct Venn diagram
A1: cao