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Is z an odd integer?

This topic has 1 expert reply and 0 member replies

Is z an odd integer?

Post Wed Nov 08, 2017 4:56 am
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

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Post Wed Nov 08, 2017 12:22 pm
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.

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