Question

Which of the statements are valid?

Answer 1

A. If Susan teaches MAT 243, every student will pass. Susan is teaching MAT 243. Therefore every student will pass.
B. It is cold. Therefore it is cold and it is raining.
C. If there is a war in Europe, a treaty has been broken. A treaty has been broken. Therefore there is a war in Europe.
D. It is cold. Therefore it is cold or it is raining.
E. Lance will eat a hamburger or a salad. Lance will not eat a salad, or he will drink Pepsi. Therefore Lance will eat a hamburger and he will drink Pepsi.
F. If there is a war in Europe, a treaty has been broken. No treaty has been broken. Therefore there is no war in Europe.
G. If there are no clouds in the sky, it will be hot. If it's hot, people will buy more water. Therefore, if there are no clouds in the sky, people will buy more water.

I'm sure A is valid, but not sure how to approach the rest...