Bunuel
Bunuel
How many different prime factors does positive integer n have?
(1) 44 < n^2 < 99
(2) 8n^2 has twelve factors
Kudos for a correct solution.
OFFICIAL SOLUTION:How many different prime factors does positive integer n have?(1) 44 < n^2 < 99. This implies that n can be 7, 8, or 9. Each of these numbers have 1 prime: 7, 2, and 3, respectively. Sufficient.
(2) 8n^2 has twelve factors. For \(8n^2=2^3n^2\) to have twelve factors n must be a prime: \(2^3*(prime)^2\) --> number of factors = (3+1)(2+1)=12. Sufficient.
Answer: D.
BunuelJust for clarification,
in Statement 2, n can be any prime number but not 2. As when n = 2, 8n^2 = 32 will have 6 factors. (1,2,4,8,16,32)
Though the answer won't change.