Foundation June 2017 Paper 3 Q9
9
(a) List all the factors of 30 [2 marks]
(b) A factor of 30 is chosen at random.
What is the probability that it is a 2-digit number? [1 mark]
| Answer | Mark | Comments |
|---|---|---|
| 1, 2, 3, 5, 6, 10, 15, 30 | B2 | B1 for one, two or three omissions or incorrect numbers |
Additional guidance
| Accept factors as products eg \(1 \times 30\) | |
| Accept factors as pairs in brackets eg (1,30) | |
| Disregard any repeated factors or reversed factor pairs | |
| Disregard any negative factor pairs \(-5 \times -6\) | |
| 1, 2, 3, 5, 6, 10, 15, 30 shown in working 1, 2, 3, 5, 6, 10, 15 on answer line (Allow transcription error) | B2 |
| 1, 2, 3, 4, 5, 6, 10, 12, 15 (one omission of 30 and two incorrect numbers in 4 and 12) | B1 |
| Answer | Mark | Comments |
|---|---|---|
| \(\dfrac{3}{8}\) | B1ft | oe fraction, decimal or percentage ft their list in (a) with at least four numbers, at least one of which is two-digit |
Additional guidance
| \(\dfrac{3}{8}\) is B1, if not \(\dfrac{3}{8}\) refer to 9(a) for possible ft | |
| 0.375 or 37.5% | B1 |
| Ignore further working with description of probability eg \(\dfrac{3}{8}\) unlikely | B1 |
| Ignore further working with attempts to convert to percentage or decimal eg \(\dfrac{3}{8}\) = 37% or 38% | B1 |
| 3 : 8 in working with \(\dfrac{3}{8}\) on answer line | B1 |
| 37% or 38% without \(\dfrac{3}{8}\) or 37.5% in working | B0 |
| 3 : 8 on answer line | B0 |
| 3 out of 8 without \(\dfrac{3}{8}\) in working | B0 |