SAT MATH IIC--Logic Problem!

Test Preparation
1

<p>According to the Dr. Chung book, the negation of “Some numbers are even” is “All numbers are not even.”</p>

<p>According to the McGrawHills Book, the negation of “All right angles measure 90 degrees” is “All right angles do not measure 90 degrees.”</p>

<p>so who is right?</p>

2

<p>Dr. Chung is right. The negation of “all right angles measure 90 degrees” is “some right angles do not measure 90 degrees.”</p>

3

<p>Dr. Chung’s negation is correct, and McGraw Hill’s is incorrect. The correct way of negating “All right angles measure 90 degrees” is as elunium said, or in other words, “At least one right angle does not measure 90 degrees.”</p>