Homework #2 (deduction and induction)

Are these deductive or inductive?

1. The sum of the interior angles of any triangle is 180°. In triangle #1, angle A is 30°, angle B is 90°. Therefore, angle C is 60°. 
2. If I get an A, then I will pass this course. Odds are, I will make a B. So, I probably won't pass this course. 
3. The platypus is not a mammal (google & find out) because no mammal lays eggs, and the female platypus does.
4. The last time I ate here, the shrimp dish I ordered was disgusting. It must be the case that this restaurant buys lousy seafood. 
5. The sign on the candy machine reads "Out of Order." The candy machine must be broken. 

are these valid or invalid? 

1. If it rained, the streets are wet. The streets are wet, so it must have rained. 
2. If Richard Roe is willing to testify then he's innocent. He's not willing to testify therefore he's not innocent. 
3. If Bogotá is north of New Orleans and New Orleans is north of Mexico City, then Bogota is north of Mexico City. 

are these strong or weak? 

4. Every day you've lived has been followed by another day in which you've been alive. Therefore, everyday you ever will live will be followed by another day in which you are alive. 
5. Nobel prize-winning biologist Herbert Ralls says that chlorinated hydrocarbons in our water supply constitute a major threat to the public health. Since no scientists disagree with him on this point. Accordingly, we conclude that the presence of these chemicals is a threat.
6. Every day you've ever lived has been a day before tomorrow, so, every day you will ever live will be a day before tomorrow.