1MA0 Foundation June 2016 Paper 2 Q16
*16 There are only black balls and white balls in bag A and in bag B, as shown in the diagram.
Heidi is going to take at random a ball from bag A and a ball from bag B.
Which bag gives Heidi the greater probability of taking a black ball, bag A or bag B?
You must show how you get your answer. (3)
| Answer | Mark | Notes |
|---|---|---|
| Bag A (supported) | 3 | M1 for \(\frac{3}{7}\) or \(\frac{5}{12}\) M1 (dep) for method to compare the two probabilities, e.g using a common denominator, eg \(\frac{3}{7} = \frac{36}{84}\); \(\frac{5}{12} = \frac{35}{84}\) or writing as decimals eg \(\frac{3}{7} = 0.428571...\) and \(\frac{5}{12} = 0.416666...\) C1 (dep on M2) for Bag A and correct method of comparison with correct figures using \(\frac{3}{7}\) and \(\frac{5}{12}\) |