4MA0 Higher January 2012 Paper 4 Q16
16 Here are 8 dominoes.
The 8 dominoes are put in a bag.
Riaz takes at random a domino from the bag.
Helima takes at random 2 dominoes from the bag of 8 dominoes without replacement.
| Scheme | Marks |
|---|---|
| \(\frac{3}{8} + \frac{2}{8}\) oe | M1 |
| \(\frac{5}{8}\) | A1 |
| (2) |
Notes
Apart from Questions 3, 13(b) and 17(f) (where the mark scheme states otherwise), the correct answer, unless clearly obtained by an incorrect method, should be taken to imply a correct method.
| Scheme | Marks |
|---|---|
| (i) \(\frac{2}{8} \times \frac{1}{7}\) appearing once only | M1 |
| \(\frac{2}{56}\) or \(\frac{1}{28}\) | A1 |
| (ii) \(\frac{2}{8} \times \frac{3}{7} + \frac{3}{8} \times \frac{2}{7}\) or \(2 \times \frac{2}{8} \times \frac{3}{7}\) oe | M1 |
| M1 | |
| \(\frac{12}{56}\) | A1 |
| (5) | |
| (Total 7 marks) |
Notes
A1: for \(\frac{2}{56}\) or \(\frac{1}{28}\) or for 0.036 or for answer rounding to 0.036
M1: for one correct product
M1: for completely correct expression
A1: for \(\frac{12}{56}\) oe inc \(\frac{3}{14}\) or for 0.21 or for answer rounding to 0.21
(b)(i): Sample space method – award 2 marks for correct answer; otherwise no marks
Note for (b)(ii): sample space method – award 3 marks for correct answer; otherwise no marks
SC M1 for \(\frac{2}{8} \times \frac{3}{8}\) or \(\frac{3}{8} \times \frac{2}{8}\)
M1 (dep) for \(\frac{2}{8} \times \frac{3}{8} + \frac{3}{8} \times \frac{2}{8}\) oe
SC Sample space method – award 2 marks for \(\frac{12}{64}\) oe; otherwise no marks