Is the integer n odd?
(1) n is divisible by 3
(2) 2n is divisible by twice as many positive integers as n
Stmt 1: Let n =6 divisible by 3 but even. Let n = 9 odd and divisible by 3. So insuff.
Stmt2: Let n = 7 (a prime number) factors 1,7. 2n = 14 factors = 1,2,7,14 = There are twice as many factors as n.
Let n = 9 (odd number but not prime) factors = 1,3,9. 2n = 18 factors = 1,2,3,6,9,18 (There are twice as many factors)
Let n = 4 factors = 1,2,4 2n= 8 factors = 1,2,4,8 (Thre are no twice as many factors)
So stmt 2 is suff.