Higher November 2024 Unit 1 Q17
17. Megan is a netball player.
She repeatedly attempts to throw the ball through the net.
On each throw, the probability that Megan gets the ball through the net is 0·7.
Each throw is independent of any previous throw.
Megan claims that the probability of getting the ball through the net for the first time on either the first or second throw is greater than 90%.
Is Megan correct?
Yes ☐ No ☐
You must show all your working. [3]
| Scheme | Marks | Comments |
|---|---|---|
| (Probability =) 0·7 + 0·3 × 0·7 OR 1 − 0·3 × 0·3 | M2 | Accept 0·7 × 0·7 + 0·7 × 0·3 + 0·3 × 0·7 M1 for sight of 0·3 × 0·7 or 0·7 × 0·3 or 0·3 × 0·3. May be seen alongside tree diagram. |
| = 0·91 AND Yes ticked or implied. | A1 |