If m is a positive odd integer between 2 and 30, then m is divisible by how many different positive prime numbers?
(1) m is not divisible by 3.
(2) m is not divisible by 5.
The OA is A.
What is the best approach for this DS question?
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If m is a positive odd integer between 2 and 30 . . .
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m is one among 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, and 29.M7MBA wrote:If m is a positive odd integer between 2 and 30, then m is divisible by how many different positive prime numbers?
(1) m is not divisible by 3.
(2) m is not divisible by 5.
The OA is A.
What is the best approach for this DS question?
(1) m is not divisible by 3.
=> m is one among 5, 7, 11, 13, 17, 19, 23, 25, and 29.
Except 25, all the integers above are prime and are divisible only by themselves. Integer 25 is also divisible by only one prime number, 5. Thus the answer is one. Sufficient.
(2) m is not divisible by 5.
=> m is one among 3, 7, 9, 11, 13, 17, 19, 21, 23, 27, and 29.
Case 1: If m is one among 3, 7, 9, 11, 13, 17, 19, 23, 27, and 29, the answer is one.
Case 2: If m is 21, m is divisible by two prime numbers (3 and 7), the answer is two.
No unique answer. Insufficient.
The correct answer: A
Hope this helps!
-Jay
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