The following arguments depend for their validity on suppressed premises of various kinds. For each of them, list enough suppressed premises to make the argument valid and also to show why it is valid. This might require several suppressed premises of various kinds.
EXAMPLE:
Carol has no sisters, because all her siblings are brothers.
SUPPRESSED Premises: A sister would be a sibling.
A brother is not a sister.
1. Britney Spears is under age thirty-five. Therefore, she cannot run for president of the United States.
2. Nixon couldn't have been president in 1950 because he was still in the Senate.
3. 81 is not a prime number, because 81 is divisible by 3 .
4. There's no patient named Rupert here; we have only female patients.
5. Columbus did not discover the New World because the Vikings explored Newfoundland centuries earlier.
6. There must not be any survivors, since they would have been found by now.
7. Lincoln could not have met Washington, because Washington was dead before Lincoln was born.
8. Philadelphia cannot play Los Angeles in the World Series, since they are both in the National League.
9. Mildred must be over forty-three, since she has a daughter who is thirtysix years old.
10. He cannot be a grandfather because he never had children.
11. That's not modern poetry; you can understand it.
12. Harold can't play in the Super Bowl, because he broke his leg.
13. Shaquille must be a basketball player, since he is so tall.
14. Dan is either stupid or very cunning, so he must be stupid.
15. Susan refuses to work on Sundays, which shows that she is lazy and inflexible.
16. Jim told me that Mary is a professor, so she can't be a student, since professors must already have degrees.
17. This burglar alarm won't work unless we are lucky or the burglar uses the front door, so we can't count on it.
18. His natural talents were not enough; he still lost the match because he had not practiced sufficiently.