Foundation November 2017 Paper 1 Q9
9 In a game, three stars are hidden at random.
Each star is behind a different square on this board.
(a) A square is chosen at random.
What is the probability that there is a star behind it? [1 mark]
(b) In one game, the stars are behind three consecutive squares.
The squares are in one row or one column.
One of the squares is E2
Write down all the possible pairs for the other two squares. [2 marks]
| Answer | Mark | Comments |
|---|---|---|
| \(\dfrac{3}{25}\) or 0.12 or 12% | B1 | oe fraction, decimal or percentage |
Additional guidance
| Do not accept ratios | |
| Ignore use of words eg 3 out of 25 = \(\dfrac{3}{25}\) eg 3 in 25 (only) | B1 B0 |
| 12 | B0 |
| Ignore attempts to simplify \(\dfrac{3}{25}\) eg \(\dfrac{3}{25} = \dfrac{1}{8}\) (attempt to simplify) \(\dfrac{3}{25} = 0.03\) (attempt to convert to a decimal) \(\dfrac{3}{25} = 3 : 25\) (choice) | B1 B1 B0 |
| Answer | Mark | Comments |
|---|---|---|
| E1, E3 and E3, E4 and C2, D2 | B2 | B1 for 1 pair correct and 0 incorrect or 2 pairs correct and 0 incorrect or 2 pairs correct and 1 incorrect or 3 pairs correct and 1 incorrect or E1, E3, (E3), E4, C2 and D2 listed, but not clearly in pairs and with no additional squares other than E2 listed |
Additional guidance
Accept 1E for E1 etc
Ignore listing of E2 if included
Ignore any annotations on diagram
If pairings seen in working, allow list without pairings on answer line