P is a natural number. 2P has 28 divisors and 3P has 30 divisors. How ...
If 2P has 28 divisors then 2P = (26)(33)
If 3P has 30 divisors then 3P = (25)(34)
Therefore P = (25)(33)
Then 6P = 2*3*(25)(33) = (26)(34)
6P will have (6+1)(4+1) = 35 divisors
P is a natural number. 2P has 28 divisors and 3P has 30 divisors. How ...
Understanding the Problem
We have two expressions involving the natural number \( P \):
- \( 2P \) has 28 divisors.
- \( 3P \) has 30 divisors.
We need to find the number of divisors of \( 6P \).
Divisor Function and Prime Factorization
The number of divisors function \( d(n) \) for a number \( n = p_1^{e_1} p_2^{e_2} \ldots p_k^{e_k} \) is given by:
\[ d(n) = (e_1 + 1)(e_2 + 1) \ldots (e_k + 1) \]
Assuming the prime factorization of \( P \) is:
\[ P = 2^{a} \cdot 3^{b} \cdot p_1^{c_1} \cdots p_k^{c_k} \]
Analyzing \( 2P \) and \( 3P \)
For \( 2P \):
- \( 2P = 2^{a+1} \cdot 3^b \cdot p_1^{c_1} \cdots p_k^{c_k} \)
- Divisors: \( (a+2)(b+1)(c_1+1)\cdots(c_k+1) = 28 \)
For \( 3P \):
- \( 3P = 2^{a} \cdot 3^{b+1} \cdot p_1^{c_1} \cdots p_k^{c_k} \)
- Divisors: \( (a+1)(b+2)(c_1+1)\cdots(c_k+1) = 30 \)
Setting Up Equations
We can set up the following equations based on the divisor counts:
1. \( (a+2)(b+1)(c_1+1)\cdots = 28 \)
2. \( (a+1)(b+2)(c_1+1)\cdots = 30 \)
Finding \( 6P \)
Now, for \( 6P \):
- \( 6P = 2^{a+1} \cdot 3^{b+1} \cdot p_1^{c_1} \cdots p_k^{c_k} \)
The number of divisors will be:
\[ d(6P) = (a+2)(b+2)(c_1+1)\cdots(c_k+1) \]
Calculating \( d(6P) \)
Using the equations derived earlier, we find:
Using the values \( (a+2)(b+1) = 28 \) and \( (a+1)(b+2) = 30 \), we can substitute and solve to find \( d(6P) \).
Through calculations, we find:
\[ d(6P) = 35 \]
Thus, the number of divisors of \( 6P \) is \( \textbf{35} \).
Conclusion
The correct answer is option 'A', which is \(