shelrod007
How many distinct prime divisors does a positive integer \(n\) have?
(1) \(2n\) has one distinct prime divisor.
(2) \(3n\) has one distinct prime divisor.
M18-37
How many different prime numbers are factors of the positive integer \(n\) ? (1) \(2n\) has one prime factor.
Clearly, the sole prime factor of \(2n\) is 2. Thus, possible values for \(2n\) include 2, 4, 8, etc., implying \(n\) could be 1, 2, 4, and so forth. If \(n=1\), it doesn't have any prime factor, but if \(n\) takes any other value (2, 4, ...), it has one prime factor: 2. Not sufficient.
(2) \(3n\) has one prime factor.
The situation here mirrors the first: the only prime factor of \(3n\) is 3. Hence, \(3n\) could be 3, 9, 27, etc., which implies \(n\) could be 1, 3, 9, and so on. If \(n=1\), then it doesn't have a prime factor, but if \(n\) takes any other value (3, 9, ...), it has one prime factor: 3. Not sufficient.
(1)+(2) From above, the only possible value of \(n\) is 1, and 1 does not have any prime factors. Sufficient.
Answer: C
I understand that n=1 is common case for both statements.
However, if we combine the 2 statements, we get 2n and 3n have 1 distinct prime divisor.