SOLUTION: FIND THE NUMBER OF DIVISORS OF 1050. SHOW ALL WORK. SOLVE. P(n,3)=24C(n,4)

Algebra ->  Permutations -> SOLUTION: FIND THE NUMBER OF DIVISORS OF 1050. SHOW ALL WORK. SOLVE. P(n,3)=24C(n,4)       Log On


   



Question 1156615: FIND THE NUMBER OF DIVISORS OF 1050. SHOW ALL WORK.
SOLVE. P(n,3)=24C(n,4)


Answer by greenestamps(13203) About Me  (Show Source):
You can put this solution on YOUR website!


Number of divisors of 1050....

(1) Find the prime factorization of 1050: (2^1)(3^1)(5^2)(7^1)
(2) Add one to each exponent and multiply: 2*2*3*2 = 24

The number of divisors of 1050 is 24.

Explanation....

Given the prime factorization of 1050, every divisor of 1050 can contain only prime factors of 2, 3, 5, and/or 7. When building a factor of 1050 from the prime factorization, there are...
2 choices for the number of factors of 2 (0 or 1)
2 choices for the number of factors of 3 (0 or 1)
3 choices for the number of factors of 5 (0, 1, or 2)
2 choices for the number of factors of 7 (0 or 1)

The total number of ways to build a divisor of 1050 is then 2*2*3*2.

Solve P(n,3) = 24C(n,4)....

P%28n%2C3%29+=+n%28n-1%29%28n-2%29
C%28n%2C4%29+=+%28n%28n-1%29%28n-2%29%28n-3%29%29%2F%284%2A3%2A2%2A1%29

n%28n-1%29%28n-2%29+=+24%2A%28%28n%28n-1%29%28n-2%29%28n-3%29%29%2F24%29

Cancel the common factors n, n-1, and n-2:

1+=+n-3
n+=+4

ANSWER: n=4

CHECK:

P(4,3) = 4*3*2 = 24
24C(4,4) = 24*1 = 24