If the river floods, then the bridge is closed. If the bridge is closed, then the school bus takes the long route. It is known that the bridge is closed. Which of the following must be true?
Correct answer C. The school bus takes the long route.
Explanation
Since the bridge is closed, the second rule shows that the school bus takes the long route. Nothing can be said about whether the river floods, because a true result does not prove its condition.
Answer checked How we write and check questions
Discussion