1. Some cars are Porsches and all Porsches are German-made. So, some cars are German-made.
2. 85% of students favor lowering student fees for the coming semester. Therefore, Liz, who is a student, almost certainly favors lowering student fees for the coming semester
3. According to www.irs.gov, child care deductions are only available for working parents. As a result, Mary, who is not working, is not eligible for this credit.
4. Professor Lucky did not commit the murder. This follows from these two facts: a) he was out of the country when the murder was committed, and b) if anyone was out of the country when the murder was committed, that person did not commit the murder.
5. Karl Marx wrote the Communist Manifesto unless John McCain did. But McCain did not write it, so Marx wrote the Communist Manifesto.
6. Given that Iceland was settled by the Norse and the people of Iceland have lived in relative isolation from other cultural influences for many centuries, it’s unlikely that modern Icelandic has changed that much since the time of the first settlers because languages usually change because of the outside influence from other people.
7. The pop-up message on your computer screen says, ‘Earn $10,000 per week. Call 306-981-3245’. Therefore, if you call that number you can earn $10,000 per week.
8. Henry and Carl, who are neighbors, are about the same age, and they both have heart conditions. Henry takes Digitoxin for his heart, and it relieves his symptoms. Therefore, it may be a good idea for Carl to take the same medicine for his heart.
9. Some people in Wisconsin are alcoholics. So some people in Wisconsin are addicts, since being an alcoholic is sufficient for being an addict.
B. Indicate whether the following arguments are valid or invalid. Explain why the argument is valid or invalid.
10. If Mia knows some logic, then I can know some, too. Since Mia does know some logic, then I can know some, too.
11. If the temperature is set to 75 degrees, the plants thrive. The temperature is not set to 75 degrees, so the plants aren’t thriving.
12. This argument is valid. Is it sound? Explain. ‘All dogs are animals. No animals are carnivorous. So no dogs are carnivorous’.
13. The following argument is strong. Is it cogent? Explain. ‘Most people in New York State vote for Democrats. So Donald Trump, who is a New York resident, probably voted for the Democratic candidate for President in the last election’.