Is positive integer r an even number?
a) r is a prime number
b) 3<r<26
OAB But I think it should be C. Comments?
a) r is a prime number
b) 3<r<26
OAB But I think it should be C. Comments?
(1) The only even prime number is 2. Choose r = 2, r is even. Choose r = 3, r is odd. Insufficient.
(2) Choose r = 4. r is even. Choose r = 5. r is odd. Insufficient.
(1)+(2) Since 2 is the only even prime number, and the range of r given in (2) excludes 2, then r must be odd. You can answer the question, "Is r even?" The answer is no.
The answer is C. Where is this problem from?
