How many factors of 24 x 35 x 104 are perfect squares which are great...
2
4 x 3
5 x 10
4=24 x 35 x 24 * 54
=28 x 35 x 54
For the factor to be a perfect square, the factor should be even power of the number.
In 28, the factors which are perfect squares are 20, 22, 24, 26, 28 = 5
Similarly, in 35, the factors which are perfect squares are 30, 32,34 = 3
In 54, the factors which are perfect squares are 50, 52, 54 = 3
Number of perfect squares greater than 1 = 5*3*3-1
=44
How many factors of 24 x 35 x 104 are perfect squares which are great...
Solution:
Prime factorization of 24 = 2^3 x 3^1
Prime factorization of 35 = 5^1 x 7^1
Prime factorization of 104 = 2^3 x 13^1
Multiplying these three numbers together gives us:
24 x 35 x 104 = 2^6 x 3^1 x 5^1 x 7^1 x 13^1
Perfect Squares
For a number to be a perfect square, all of its prime factors must have even exponents. Therefore, the prime factorization of a perfect square must be of the form:
p1^e1 x p2^e2 x ... x pn^en, where all the exponents ei are even.
To count the number of perfect squares that are factors of 24 x 35 x 104, we will count the number of possible combinations of even exponents for each prime factor.
Prime factor 2
For the factor to be a perfect square, the exponent of 2 must be even. So, we can choose the exponent of 2 to be 0, 2, 4, or 6.
- 2^0 can be paired with all possible combinations of the other prime factors, giving us 4 possibilities.
- 2^2 can also be paired with all possible combinations of the other prime factors, giving us another 4 possibilities.
- 2^4 can be paired with all possible combinations of the other prime factors except 13^1, giving us 3 possibilities.
- 2^6 can only be paired with 3^1, 5^1, and 7^1, giving us 3 possibilities.
Total number of possibilities for prime factor 2 = 4 + 4 + 3 + 3 = 14
Prime factor 3
For the factor to be a perfect square, the exponent of 3 must be even. So, we can choose the exponent of 3 to be 0 or 2.
- 3^0 can be paired with all possible combinations of the other prime factors, giving us 4 possibilities.
- 3^2 can only be paired with 2^0, 5^1, and 7^1, giving us 3 possibilities.
Total number of possibilities for prime factor 3 = 4 + 3 = 7
Prime factor 5
For the factor to be a perfect square, the exponent of 5 must be even. So, we can choose the exponent of 5 to be 0 or 2.
- 5^0 can be paired with all possible combinations of the other prime factors, giving us 4 possibilities.
- 5^2 can only be paired with 2^0 and 3^0, giving us 2 possibilities.
Total number of possibilities for prime factor 5 = 4 + 2 = 6
Prime factor 7
For the factor to be a perfect square, the exponent of 7 must be even. So, we can choose the exponent of 7 to be 0 or 2.
- 7^0 can be paired with all possible combinations of the other prime factors, giving us 4 possibilities.
- 7^2 can only be paired with 2^0 and 3^0, giving us 2 possibilities.