Date | November 2009 | Marks available | 5 | Reference code | 09N.1.hl.TZ0.6 |
Level | HL only | Paper | 1 | Time zone | TZ0 |
Command term | Find | Question number | 6 | Adapted from | N/A |
Question
At a nursing college, 80 % of incoming students are female. College records show that 70 % of the incoming females graduate and 90 % of the incoming males graduate. A student who graduates is selected at random. Find the probability that the student is male, giving your answer as a fraction in its lowest terms.
Markscheme
P M|G=P(M∩G)P(G) (M1)
=0.2×0.90.2×0.9+0.8×0.7 M1A1A1
=0.180.74
=937 A1
[5 marks]
Examiners report
Most candidates answered this question successfully. Some made arithmetic errors.