Higher November 2019 Paper 6 Q13
13 Dani has a pack of 45 cards.
Each card is either red or black.
One-third of the cards in the pack are red.
She picks two cards from the pack, without replacement.
Calculate the probability that Dani picks two black cards. [5]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| \(\frac{29}{66}\) oe | 5 | M4 for \(\frac{2}{3} \times \frac{29}{44}\) OR B1 for [p(black) =] \(\frac{2}{3}\) oe soi and B2 for \(\frac{29}{44}\) or B1 for \(\frac{n}{44}\) with \(0 \lt n \lt 44\) or B1 for \(\frac{29}{45}\) and M1 for \(\frac{2}{3} \times \textit{their}\ \frac{n}{44}\) or \(\frac{2}{3} \times \frac{29}{45}\) | oe e.g. \(\frac{870}{1980}\) or 0.439… or 0.44 after correct working |