Conjunction fallacy

Question

MY apologies if this is off-topic. I am not sure if its tested in GMAT CR but it centainly is interesting and very easy to fall into trap. Check it out:

Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations. 

Which is more likely?

1. Linda is a bank teller.
2. Linda is a bank teller and is active in the feminist movement. 


If anyone came across some CR that tests this, please let us know.

sandalphon · Answer

Ok I will take the risk to fall into that trap. It is more likely that she is A, because nowhere in the passage does she say that she involved in some kind of feminist activity. If you skim through the passage one might allude that she mighthave feminist tendencies but nowhere does it say so. can you post OA please, to see if I fell into that trap? 8-)

Bhai · Answer

2.

Agree that the feminist activist is not metioned anywhere but still she works on issues of social justice and discrimination.

duttsit · Answer

well, we need use math rather than reason to avoid falling into trap. As we know: probability of p(A and B) < p(A) p(A and B) < p(B) the fist one will always be more likely than the second

taquanghai · Answer

Very interesting question.

The first is the answer

Conjunction fallacy

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