Math Problem Statement

If A is the sum of the factors of 72. Then what is the product of all the factors of A? (1) (195)8 (2) (195)4 (3) 1950 (4) 72A

Solution

To solve the problem, we first need to find the sum of the factors of 72 (denoted as AA) and then the product of all the factors of AA.

Step 1: Find the prime factorization of 72

The prime factorization of 72 is: 72=23×3272 = 2^3 \times 3^2

Step 2: Use the formula for the sum of the factors

The formula for the sum of the factors of a number nn is given by: σ(n)=(1+p1+p12++p1k1)(1+p2+p22++p2k2)\sigma(n) = (1 + p_1 + p_1^2 + \cdots + p_1^{k_1})(1 + p_2 + p_2^2 + \cdots + p_2^{k_2}) \cdots where p1,p2,p_1, p_2, \dots are the prime factors, and k1,k2,k_1, k_2, \dots are their respective powers in the prime factorization of nn.

For n=72n = 72, we apply the formula: σ(72)=(1+2+22+23)(1+3+32)\sigma(72) = (1 + 2 + 2^2 + 2^3)(1 + 3 + 3^2)

Simplifying: 1+2+4+8=151 + 2 + 4 + 8 = 15 1+3+9=131 + 3 + 9 = 13 σ(72)=15×13=195\sigma(72) = 15 \times 13 = 195

Thus, A=195A = 195.

Step 3: Find the product of all factors of AA

The product of all the factors of a number nn is given by nt(n)/2n^{t(n)/2}, where t(n)t(n) is the number of divisors of nn.

Step 4: Find the number of divisors of A=195A = 195

The prime factorization of 195 is: 195=3×5×13195 = 3 \times 5 \times 13 The number of divisors t(n)t(n) is found by adding 1 to the exponents in the prime factorization and then multiplying: t(195)=(1+1)(1+1)(1+1)=2×2×2=8t(195) = (1+1)(1+1)(1+1) = 2 \times 2 \times 2 = 8

Step 5: Compute the product of all divisors

The product of all divisors of A=195A = 195 is: 195t(195)/2=1958/2=1954195^{t(195)/2} = 195^{8/2} = 195^4

Thus, the product of all the factors of AA is 1954195^4.

Final Answer:

The correct answer is: (195)4\boxed{(195)^4}


Do you want more details or have any questions?
Here are 5 related questions for further practice:

  1. What is the sum of the factors of 100?
  2. How many divisors does 180 have?
  3. What is the product of the factors of 48?
  4. Find the sum of divisors of 144.
  5. How do you calculate the product of the factors of a prime number?

Tip: The sum of divisors formula can help simplify divisor-related problems, especially when working with factorized numbers.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Number Theory
Prime Factorization
Divisors
Sum of Factors
Product of Factors

Formulas

Sum of divisors: σ(n) = (1 + p1 + p1^2 + ... + p1^k1)(1 + p2 + ... + p2^k2)...
Product of divisors: n^(t(n)/2), where t(n) is the number of divisors

Theorems

Divisor Function Theorem

Suitable Grade Level

Grades 9-12