Try TESTING CASES here:
Is z an odd integer?
(1) z is divisible by 3.
If z = 9, then yes: z is odd.
If z = 6, then no: z is not odd.
We tested 2 values that both fit the statement, and we got one yes and one no. Insufficient.
(2) The square root of z is an integer divisible by 3.
If the square root of z is divisible by 3, then z must be a perfect square that is divisible by 3. Again, test cases that fit:
If z = 9, then yes: z is odd.
If z = 36, then no: z is not odd.
Insufficient.
Putting the statements together does not help, because we already know statement 1 in knowing statement 2. Therefore, the answer must be E.
Ceilidh Erickson
EdM in Mind, Brain, and Education
Harvard Graduate School of Education
