To find the required sum, \( p+q \), we need to evaluate two conditions for elements \( (m,n) \) in the set \( S = \{ (m,n) : m,n \in \{1, 2, 3, \dots, 50\} \} \).
Step 1: Calculate \( p \), the number of elements where \( 6^m + 9^n \equiv 0 \pmod{5} \).
Since \( 6 \equiv 1 \pmod{5} \) and \( 9 \equiv 4 \pmod{5} \), we have:
We need \( 1 + 4^n \equiv 0 \pmod{5} \rightarrow 4^n \equiv -1 \equiv 4 \pmod{5} \).
This holds when \( n \) is odd since the cycle of \( 4^n \) is: \(4, 1, 4, 1, \ldots\).
Thus, for 25 odd values of \( n \), \( m \) can be any of the 50 values from 1 to 50.
Therefore, \( p = 50 \times 25 = 1250 \).
Step 2: Calculate \( q \), the number of elements where \( m+n \) is a square of a prime number.
Count solutions for each square:
| Square | Solutions |
| 4 | 3 (pairs: (1,3), (2,2), (3,1)) |
| 9 | 8 (pairs: (1,8), (2,7), ..., (8,1)) |
| 25 | 24 (pairs from (1,24) to (24,1)) |
| 49 | 48 (pairs from (1,48) to (48,1)) |
Thus, \( q = 3 + 8 + 24 + 48 = 83 \).
Final Calculation:
\( p + q = 1250 + 83 = 1333 \).
This falls within the given range [1333,1333]. Hence, the final value is \( \boxed{1333} \).
Let S be the set of the first 11 natural numbers. Then the number of elements in $A = \{B \subseteq S : n(B) \geq 2$ and the product of all elements of B is even is ________.
Let S be the set of the first 11 natural numbers. Then the number of elements in $A = \{B \subseteq S : n(B) \geq 2$ and the product of all elements of B is even is ________.