Is z an odd integer?
(1) z is divisible by 3.
(2) The square root of z is an integer divisible by 3.
Isn't statement 1 sufficient?
OA E
Is z an odd integer?
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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.
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
EdM in Mind, Brain, and Education
Harvard Graduate School of Education