If a and b are both prime numbers greater than 10, which of the following CANNOT be true?
I. ab is an even number.
II. a - b = 117.
III. The sum of a and b is even.	Choose the most appropriate option.
A) I and II only	B) I only	C) I and III only	D) II and III only	E) I, II and III
MANHATTAN GMATOFFICIAL SOLUTION:   Since a and b are both prime numbers greater than 10, they must both be odd. Therefore ab must be an odd number, so Statement I cannot be true. Similarly, if a and b are both odd, then a - b cannot equal 117 (an odd number). This difference must be even. Therefore, Statement II cannot be true. Finally, since a and b are both odd, a + b must be even, so Statement III will always be true. Since Statements I and II CANNOT be true, but Statement III IS true,the correct answer is (A).   I and II onlynswer : I and II only
<result>A</result>
If a and b are both prime numbers greater than 10, which of the following CANNOT be true?
I. ab is an even number.
II. a - b = 117.
III. The sum of a and b is even.