Answer
Mount McKinley is the highest in the United States.
Work Step by Step
Because one conclusion matches the other hypothesis, The Law of Syllogism allows us to conclude:
If an Alaskan mountain is more than 20,300 ft high, then it is the highest in the United States.
Because the hypothesis matches the given statement about Mount McKinley (more than 20,300 ft high), the Law of Detachment then allows us to conclude:
Mount McKinley is the highest in the United States.
