If r and s are positive integers, is r/s an integer?
1) Every factor of s is also a factor of r
2) Every prime factor of s is also a prime factor of r.
Every integer can be written in terms of its prime factors and total number of factors will depend on the frequency of such prime factors.
Statement 1) says that all the factors of s are also factors of r, so r + K*s where K is an integer and hence r/s is an integer - Sufficient
Statement 2) says that all the prime factors of s are also prime factors of r, but we do not know the frequency of these prime numbers and hence do not know about other factors of r and s and hence cant say if r/s is an integer. If r is greater than s, then r/s is integer whereas if s is greater than r, it is not (lets say two numbers 2*3 and 2*3*3 have same prime factors 2 and 3, but their ratio can be an integer or not depending on which one is in numerator) - Insufficient