LSAT 70, Logical Reasoning I, Q22

QUESTION TEXT: In marketing their products, drug companies often …

QUESTION TYPE: Must Be True

FACTS:

1. Most physicians don’t think that they’re influenced by gifts.
2. Most physicians think that other physicians are influenced by gifts.

ANALYSIS: This question tests a rare deduction. If you combine two most statements, they have to overlap, and you can conclude a ‘some’ statement. I’ll prove it with a small example. Let’s imagine three doctors: Smith, Lopez and Dietrich.

There are just three doctors, so two out of three of them equals ‘most’ doctors. So let’s say that Smith and Lopez both believe that the other two doctors are guilty AND let’s say that both Smith and Lopez believe that they themselves are innocent.

• People who think they are innocent: Smith, Lopez
• People blamed by other doctors as being influenced: Smith, Lopez, Dietrich

Obviously, someone is wrong. Every doctor has been accused of being influenced, yet two of them believe they aren’t influenced.

And that’s exactly what we can conclude. At least some doctors are wrong.

___________

1. We have no idea what effect gifts actually have. The stimulus only gives us evidence about
   physicians’ beliefs. 
2. The stimulus doesn’t mention guidelines. A ‘must be true’ answer must be based on something from the stimulus.
3. CORRECT. See the example above. There are at least some doctors who believe that they are innocent and yet are accused by some other doctors.
4. The stimulus never mentioned any physicians who admit that they were influenced. We only know that ‘most’ physicians think that they are innocent: most can mean ‘all’.
5. Same as D. We have no proof that any physicians admit guilt.

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