A-LevelMathematicsProbability and statistics9709/51 · May/June 2021 · Q14 Marks
A bag contains 12 marbles, each of a different size. 8 of the marbles are red and 4 of the marbles are blue.
- (a)How many different selections of 5 marbles contain at least 4 marbles of the same colour?[4]
Mark scheme
Marking points from the official mark scheme (May/June 2021). The mark or mark type is shown in brackets.
- [M1] Cxx Cy with x + y = 5. x, y both integers, 1 ≤ x ≤ 5, 0 ≤ y ≤ 4 condone C1 × 1
- [A1] Two correct outcomes evaluated
- [M1] Add 2 or 3 identified correct scenarios only (no additional terms, not probabilities)
- [A1] WWW, only dependent on 2nd M mark
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