Foundation June 2024 Paper 1 Q3
3 A box contains 10 balls.
5 balls are black
3 balls are green
2 balls are red
Rema is going to take at random a ball from the box.
(a) On the probability scale, mark with a cross (\(\times\)) the probability that the ball is black. (1)
(b) On the probability scale, mark with a cross (\(\times\)) the probability that the ball is orange. (1)
Johan has three bags of counters, A, B and C
He tries to find the probability of taking at random a white counter from each bag.
He writes his probabilities in a table.
| Bag | A | B | C |
|---|---|---|---|
| Probability | 0.7 | 0.45 | 1.2 |
The probability that Johan writes for bag C is incorrect.
(c) Explain how you know that it is incorrect. (1)
| Scheme | Marks |
|---|---|
| Cross at \(\dfrac{1}{2}\) | B1 |
| (1) |
Notes
B1: cao
| Scheme | Marks |
|---|---|
| Cross at 0 | B1 |
| (1) |
Notes
B1: cao
| Scheme | Marks |
|---|---|
| Acceptable answers eg 1. It is over 1/more than 1 oe 2. It is over 100%/more than 100% oe 3. Probability of 1/100% is the highest oe 4. Probability ranges from 0 – 1 or 0 – 100% oe 5. 1.2/120% is impossible oe 6. It has to be 1 or less oe 7. It has to be below 1 oe Do not accept eg 1. It is (too) high oe 2. Sum has to be 1 oe This is not an exhaustive list Answer: Correct reason | B1 |
| (1) | |
| (3 marks) |
Notes
B1: for probability cannot be more than 1 oe
Do not allow contradictory answers
Any reference to sum of probabilities is 1 is B0