Unit 4 Answers

15.

1. If the wind blows from the northeast, then it snows.
2. If it stays warm for a week, then the apple trees will bloom.
3. If the Pistons win the championship, then they beat the Lakers.
4. If you get to the top of Long's Peak, then you must have walked 8 miles.
5. If you are world-famous, then you will get tenure as a professor.
6. If you drive more than 400 miles, then you will need to buy gasoline.
7. If you guarantee is good, then you must have bought your CD player less than 90 days ago.

17.

1. You buy an ice cream cone if and only if it is hot outside.
2. You win the contest if and only if you hold the only winning ticket.
3. You get promoted if and only if you have connections.
4. Your mind will decay if and only if you watch television.
5. The train runs late if and only if it is a day I take the train.