Ok I just had my Probability exam today, this was a national standard in New Zealand and there was one question that left me wondering whether or not it was possible to answer or if the NZQA (New Zealand Qualifications Authority) had made a mistake. I wasn't the only one who was confused by this either..
Anyway the question was essentially:
There are 30 people on a tour bus.
22 passengers were male
8 passengers were over 30 y/o
1 passenger was a male Australian over 30 y/o
3 passengers were male Australians 30 y/o or under
All female Australians passengers were over 30 y/o
There were 2 male passengers over 30 y/o but not Australian
10 passengers were Australians
Calculate the probability that a randomly selected passenger was an Australian female over 30 y/o
The problem was that there are 4 out of the 10 Australians were male therefore the other 6 Australian passengers were female. These women are all over 30 y/o but the problem is that there are only 8 passengers over 30 y/o and in the constraints there's the 1 Australian male over 30 y/o and the 2 non-Australians who were over 30 y/o so
8-2-1= 5 ≠6
SO anyone have a solution??