Context:
We have three types of logical statements that are formed from a conditional statement. They are:
- Converses
- Inverses
- Contrapositives
Let's say the conditional statement is: If A, then B.
- Converse: If B, then A.
- Inverse: If not A, then not B.
- Contrapositive: If not B, then not A.
One important thing to note is that while these are all variations of a conditional statement, the converse and inverse are not always necessarily true.
On the other hand, the contrapositive is always true. This can be proved mathematically, and I will prove it now in an example.
Example:
A standard example would be the following conditional statement:
- If it rained last night, then the sidewalk is wet.
We agree that the original statement is true. Now, let's form the converse, inverse, and contrapositive to this statement:
- Converse: If the sidewalk is wet, then it rained last night.
While this may be true, it is not guaranteed that it rained last night. The sidewalk could be wet for other reasons than rain.
- Inverse: If it did not rain last night, then the sidewalk is wet.
This statement obviously seems flawed, as there was no rain to make the sidewalk wet. It must be wet for other reasons.
- Contrapositive: If the sidewalk is not wet, then it did not rain last night.
This statement is true and is logically equivalent to the original statement.
Answer:
Now, let's apply our knowledge of logically equivalent statements to the given conditional statement.
If he studies, he will pass the course.
- Converse: If he passes the course, he studied.
- Inverse: If he did not study, he will not pass the course.
- Contrapositive: If he did not pass the course, he did not study.
The sequence of this statement, not-B then not-A, is followed in answer choice C. Therefore, this is the correct answer choice.
Remember that if a question asks you to find the logically equivalent statement to a conditional, always look for the contrapositive.
