if n is the product of the integers from 1 to 8, inclusive, how many different primer factors greater than 1 does n have?
so n = 1*2*3*4*5*6*7*8
prime factors of those are: 2,3,5,7
so 4 prime factors?
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sfreeman wrote:if n is the product of the integers from 1 to 8, inclusive, how many different primer factors greater than 1 does n have?
1 is not a prime numberpathaniaus wrote:sfreeman wrote:if n is the product of the integers from 1 to 8, inclusive, how many different primer factors greater than 1 does n have?
product of n: 1*2*3*4*5*6*7*8
We can re-write this as:
1*2*3*(2^2)*5*(3*2)*7*(2^3)
See what I did? I reduced everything integer in the product to its factors.
Now its easy, we count all the factors greater than 1
# of 2s: 7
# of 3s: 2
# of 5s: 1
# of 7s: 1
total # of prime factors: 7+2+1+1 = 11 different prime factors. (Also note that since the question did not ask for DISTINCT or UNIQUE factors, we count all prime numbers, even as the prime numbers repeat themselves.
I hope that helped! Let me know if I am correct!
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