CCAT Syllogisms and Deductions 2

Question 1

Premises: All athletes are disciplined. All disciplined people are successful. Conclusion: All athletes are successful. Is the conclusion valid?

Accepted Answer

Valid

Answer

Valid syllogism: All A are B; All B are C; therefore All A are C. Athletes (A) are disciplined (B) are successful (C).

Question 2

Premises: No fish are mammals. All whales are mammals. Conclusion: No whales are fish. Is this valid?

Accepted Answer

Valid

Answer

Fish and mammals are disjoint. Whales are all mammals. Since no mammal is a fish, no whale is a fish. Valid.

Question 3

Premises: Some teachers are authors. All authors are creative. Conclusion: Some teachers are creative. Is this valid?

Accepted Answer

Valid

Answer

Some teachers are authors, and all authors are creative. Those teachers who are authors must be creative.

Question 4

Premises: All birds have feathers. This animal has feathers. Conclusion: This animal is a bird. Is this valid?

Accepted Answer

Invalid — affirming the consequent

Answer

This commits the fallacy of affirming the consequent. Having feathers does not mean it's a bird — the premise says all birds have feathers, not that all feathered things are birds.

Question 5

Premises: No vegetarians eat meat. Sarah eats meat. Conclusion: Sarah is not a vegetarian. Is this valid?

Accepted Answer

Valid

Answer

Contrapositive: if someone eats meat, they are not a vegetarian. Sarah eats meat, so Sarah is not a vegetarian. Valid.

CCAT Practice Test

CCAT Practice Test

CCAT Syllogisms and Deductions 2