## About This Quiz

Even if you're not Sherlock Holmes, you probably have one or two deductive bones in your body. We know that not everyone will be able to figure out every statement on this quiz. Are you game?

Most deductive arguments follow the classic reasoning pattern of if A = B and B = C, then A = C. But, just because a statement has these three components does not make it correct. To ensure that the deduction (C) is correct, the arguments (A and B) must also be correct. Consider this argument: All presidents live in the White House. George Washington was a president. Therefore, George Washington lived in the White House. Now, we know that, in fact, George Washington, as president, did not live in the White House because construction was not completed on the presidential residence until November 1800. The first statement in this argument, "All presidents live in the White House," is false. If one of the statements is false (even though the second argument, "George Washington was a president," is true), then the deduction must also be false. If course, this requires a bit of knowledge, because if you didn't know that Washington did not live in the White House, you might assume that this deduction was valid.

Are you a genius? Prove it by acing this quiz.

This deduction is valid. From the argument, we can deduce that anyone who is a person is mortal.

This deduction is valid. From the argument, we can deduce that because monkeys are mammals, they have kidneys.

This deduction is invalid. To be valid, an argument must follow the classic reasoning pattern of if A = B and B = C, then A = C. This argument does not do so.

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This deduction is valid. From the argument, we can deduce that because squares are rectangles, they must have four sides.

This deduction is valid. If the party is at work today, and Nancy does not go to work today, we can deduce that Nancy will miss the party.

This deduction is not valid. There are other cities in Ohio, which makes this argument false.

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This deduction is not valid. The argument does not say that everything black is a crow.

This deduction is valid. ALL numbers that end in 0 or 5 are divisible by 5.

This argument is valid. It is correct to deduce that any bird has feathers.

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This deduction is valid. If the argument is true, then the deduction is true.

This deduction is valid. If Fido is a dog, then, according to the argument, Fido must have a keen sense of smell.

This deduction is not valid. If the argument said "all growling dogs bite," then it might be valid.

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This deduction is valid. If all reptiles are cold-blooded, and all snakes are reptiles, then it stands to reason that snakes are cold-blooded.

This deduction is valid. From the argument, we can assume that trees perform photosynthesis.

This deduction is valid. If all red meat contains iron, then it follows that, if beef is red meat, beef contains iron.

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This deduction is not valid. The argument does not say that ALL cats are grey.

This deduction is invalid. To be valid, an argument must follow the classic reasoning pattern of if A = B and B = C, then A = C. This argument does not do so.

This deduction is valid. From the argument, we can deduce that a 40-degree angle must be acute.

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This deduction is valid. If helium is a noble gas, it must be stable.

This deduction is valid. If all cells have DNA, and lions have cells, then lions must have DNA.

This deduction is valid. From the argument, we can deduce that all Chevys have at least two doors.

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This deduction is invalid. The boyfriend might be frugal, not poor, and he might be a great guy.

This deduction is not valid. There are other cities in Ireland.

This deduction is not valid. Cause and effect does not necessarily lead to logical deductions.

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This deduction is not valid. In this case, hospitals are full of sick people, because sick people go there.

This deduction is valid. Both arguments are true, leading to a valid deduction.

This deduction is invalid. Although both arguments may, in fact, be true, they do not lead to a valid deduction.

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This deduction is invalid. To be valid, an argument must follow the classic reasoning pattern of if A = B and B = C, then A = C. This argument does not do so.

This deduction is valid. If we assume that both arguments are correct, then it follows that the deduction is also correct.

This deduction is valid. It follows that, if both arguments are correct, the deduction must also be correct.

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This deduction is valid. If all dogs have four legs, and a corgi is a dog, then it follows that corgis must have four legs.

This deduction is invalid. Although both arguments are correct, they are unrelated, so the deduction is incorrect.

This deduction is invalid. Although the arguments and the deduction statement are all correct, the arguments are unrelated.

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This deduction is valid. If a shark is a fish, then we may assume that sharks can swim.