Show that the argument is valid.
1. The auto manufacturer follows environmental regulations or they face legal action. The manufacturer does not follow environmental regulations. Therefore, the manufacturer faces legal action.
2. If the class votes for an oral final, the teacher is glad. If the exam is not scheduled for a Monday, the teacher is sad. The exam is scheduled for a Friday. Therefore, the class doesn't vote for an oral final.
3. If my allowance comes this week and I pay the rent, then my bank account will be in the black. If I do not pay the rent, I will be evicted. I am not evicted and my allowance comes. Therefore, my bank account is in the black?
4. Jane is in sixth grade implies that Jane understands fractions and Jane is in sixth grade implies that Jane is in a remedial math class. Jane is in sixth grade. Therefore, Jane understands fractions or she is in a remedial math class?