I missed this question. Please help!
If the prime numbers p and t are the only prime factors of the integer m, is m a multiple of (p^2)*t?
1) m has more than 9 positive factors
2) m is a multiple of p^3 [moderator's edit]
cesar.rodriguez.blanco Wrote:I missed this question. Please help!
If the prime numbers p and t are the only prime factors of the integer m, is m a multiple of (p^2)*t?
1) m has more than 9 positive factors
2) m is a multiple of p^3
RonPurewal Wrote:cesar.rodriguez.blanco Wrote:I missed this question. Please help!
If the prime numbers p and t are the only prime factors of the integer m, is m a multiple of (p^2)*t?
1) m has more than 9 positive factors
2) m is a multiple of p^3
we already know that m is a multiple of t, so the only real issue here is whether there are 2 copies of "p" in its prime factorization.
i.e., we already know it's a multiple of pt; all that's missing is the second "p".
(1)
this clearly could be a "yes", if m is something like (p^1000)(t^1000). therefore, the challenge lies in looking for a "no".
we can get a "no" by keeping only one "p", and just raising "t" to a huge power. for instance, m = (p)(t^1000) will have over two thousand factors.
insufficient.
(2)
if m is a multiple of p^3, then it's at least a multiple of (p^3)(t), so, sufficient.
ans = (b)
sachin.w Wrote:Hi Ron,
I don't quite understand how second statement is sufficient.
Please explain with a numerical example..
jlucero Wrote:sachin.w Wrote:Hi Ron,
I don't quite understand how second statement is sufficient.
Please explain with a numerical example..
p is a positive prime number, so p could be 2, 3, 5, 7...
If m is a multiple of p^3, it must be divisible by 8, 27, 125, 343...
The question asks if m is divisible by p^2, so if the number is divisible by p^3, it must be divisible by p^2.
If p is 2
m is divisible by 8
so m must be divisible by 4
If p is 3
m is divisible by 27
so m must be divisible by 9
etc.
sachin.w Wrote:Thanks Joe, but we are asked if m a multiple of (p^2)*t
we already know that m is a multiple of t, so the only real issue here is whether there are 2 copies of "p" in its prime factorization.
sachin.w Wrote:Thanks Ron,
Just to cement my understanding..
Say 'r' is also a prime factor of m..
So, will 'm' be a multiple of 'pr'.