Foundation June 2019 Paper 1R Q18
18
(a) Find the highest common factor (HCF) of 21 and 35 (1)
(b) Write 720 as a product of its prime factors.
Show your working clearly. (3)
Show your working clearly. (3)
(c) Find the smallest whole number that 720 can be multiplied by to give a square number. (1)
| Scheme | Marks |
|---|---|
| 7 | B1 |
| (1) |
| Scheme | Marks |
|---|---|
| e.g. 720 = 2 × 360 = 2 × 2 × 180 or 720 = 3 × 240 = 3 × 3 × 80 etc | M1 |
| 2, 2, 2, 2, 3, 3, 5 | M1 |
| 2 × 2 × 2 × 2 × 3 × 3 × 5 | A1 |
| (3) |
Notes
M1: At least 2 correct stages in prime factorisation
M1: condone inclusion of 1 (may be a fully correct factor tree or ladder)
A1: dep on M2, accept \(2^4 \times 3^2 \times 5\)
| Scheme | Marks |
|---|---|
| 5 | B1 |
| (1) | |
| (5 marks) |