| Date | May 2017 | Marks available | 3 | Reference code | 17M.1.sl.TZ1.7 |
| Level | SL only | Paper | 1 | Time zone | TZ1 |
| Command term | Find | Question number | 7 | Adapted from | N/A |
Question
Sara regularly flies from Geneva to London. She takes either a direct flight or a non-directflight that goes via Amsterdam.
If she takes a direct flight, the probability that her baggage does not arrive in London is 0.01.
If she takes a non-direct flight the probability that her baggage arrives in London is 0.95.
The probability that she takes a non-direct flight is 0.2.
Complete the tree diagram.
Find the probability that Sara’s baggage arrives in London.
Markscheme
(A1)(A1)(A1) (C3)
Note: Award (A1) for each correct pair of probabilities.
[3 marks]
\(0.8 \times 0.99 + 0.2 \times 0.95\) (A1)(ft)(M1)
Note: Award (A1)(ft) for two correct products of probabilities taken from their diagram, (M1) for the addition of their products.
\( = 0.982{\text{ }}\left( {98.2\% ,{\text{ }}\frac{{491}}{{500}}} \right)\) (A1)(ft) (C3)
Note: Follow through from part (a).
[3 marks]
