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Problem: Define \[p = \sum_{k = 1}^ \infty \frac{1}{k^2} \quad \text{and} \quad q = \sum_{k = 1}^\infty \frac{1}{k^3}.\]Find a way to write \[\sum_{j = 1}^\infty \sum_{k = 1}^\infty \frac{1}{(j + k)^3}\] in terms of $p$ and $q.$
Predicted answer (BoN): To solve the given problem, we need to express the double sum \(\sum_{j=1}^\infty \sum_{k=1}^\infty \frac{1}{(j+k)^3}\) in terms of \(p\) and \(q\).

First, let's analyze the inner sum \(\sum_{k=1}^\infty \frac{1}{(j+k)^3}\). This sum can be written as:

\[
\sum_{k=1}^\infty \frac{1}{(j+k)^3}
\]

We can change the order of summation. Instead of summing over \(k\) first, we sum over \(j\) first. For a fixed \(j\), \(k\) ranges from 1 to \(\infty\). When \(j\) is fixed, \(k\) can be written as \(j + (n-j)\) where \(n\) is an integer. So, the sum becomes:

\[
\sum_{k=1}^\infty \frac{1}{(j+k)^3} = \sum_{j=1}^\infty \sum_{n=1}^\infty \frac{1}{(n)^3} = \sum_{j=1}^\infty \sum_{n=1}^\infty \frac{1}{n^3}
\]

This is exactly \(q\). So we have:

\[
\sum_{j=1}^\infty \sum_{k=1}^\infty \frac{1}{(j+k)^3} = \sum_{j=1}^\infty \sum_{k=1}^\infty \frac{1}{(j+k)^3} = q
\]

Now, we need to express \(q\) in terms of \(p\) and \(q\). Recall that:

\[
p = \sum_{k=1}^\infty \frac{1}{k^2}
\]

We need to find a way to express \(q\) in terms of \(p\). Notice that:

\[
\sum_{j=1}^\infty \sum_{k=1}^\infty \frac{1}{(j+k)^3} = \sum_{j=1}^\infty \sum_{k=1}^\infty \frac{1}{j^3} \cdot \frac{1}{k^3} = \left( \sum_{j=1}^\infty \frac{1}{j^3} \right) \left( \sum_{k=1}^\infty \frac{1}{k^3} \right) = p \cdot q
\]

Thus, we have:

\[
q = \frac{p}{p} = \frac{p}{q}
\]

So, the expression for \(\sum_{j=1}^\infty \sum_{k=1}^\infty \frac{1}{(j+k)^3}\) in terms of \(p\) and \(q\) is:

\[
\boxed{q}
\]
Correct Answer: p - q
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Problem: A regular hexagon can be divided into six equilateral triangles. If the perimeter of one of the triangles is 21 inches, what is the perimeter, in inches, of the regular hexagon?
Predicted answer (BoN): ## Step 1: ##
To solve this problem, we need to understand the relationship between the side length of the equilateral triangle and the side length of the regular hexagon it's divided into.

## Step 2: ##
Given that the perimeter of one equilateral triangle is 21 inches, we know that the perimeter of a regular hexagon composed of six such equilateral triangles is simply 6 times the perimeter of one triangle because all sides of the hexagon are equal in length and they come from equilateral triangles.

Therefore, the perimeter of the hexagon is 6 * 21.

## Step 3: ##
Calculating the perimeter of the hexagon, we get 6 * 21 = 126 inches.

## Step 4: ##
Thus, the final answer is 126 inches.

Therefore, the perimeter of the regular hexagon is $\boxed{126}$.
Correct Answer: 42
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Problem: The expression $2\cdot 3 \cdot 4\cdot 5+1$ is equal to 121, since multiplication is carried out before addition. However, we can obtain values other than 121 for this expression if we are allowed to change it by inserting parentheses. For example, we can obtain 144 by writing \[ (2\cdot (3\cdot 4)) \cdot (5+1) = 144. \]In total, how many values can be obtained from the expression $2\cdot 3\cdot 4 \cdot 5 + 1$ by inserting parentheses? (Note that rearranging terms is not allowed, only inserting parentheses).
Predicted answer (BoN): To solve the problem of how many values can be obtained from the expression \(2 \cdot 3 \cdot 4 \cdot 5 + 1\) by inserting parentheses, we need to consider all possible ways to insert parentheses and evaluate the expression for each case.

Given the expression \( (a \cdot (b \cdot (c \cdot d) + e)) + f \), we need to evaluate it for all possible placements of parentheses.

### Step-by-Step Solution:

1. **Evaluate without parentheses:**
   \[
   2 \cdot 3 \cdot 4 \cdot 5 + 1 = 120 + 1 = 121
   \]

2. **Evaluate with one set of parentheses:**

   - \( (2 \cdot (3 \cdot 4) \cdot 5 + 1) \)
   
   - \( 2 \cdot ( (3 \cdot 4) \cdot 5 + 1) \)
   
   - \( (2 \cdot 3) \cdot (4 \cdot 5) + 1 \)
   
   - \( (2 \cdot 3) \cdot ( (4 \cdot 5) + 1) \)
   
   - \( 2 \cdot (3 \cdot (4 \cdot 5) + 1) \)
   
   - \( 2 \cdot ((3 \cdot 4) \cdot 5) + 1 \)
   
3. **Evaluate with two sets of parentheses:**

   - \( ((2 \cdot 3) \cdot (4 \cdot 5)) + 1 \)
   
   - \( (2 \cdot ((3 \cdot 4) \cdot 5)) + 1 \)
   
   - \( ((2 \cdot 3) \cdot (5 \cdot 4)) + 1 \)
   
   - \( (2 \cdot (3 \cdot (4 \cdot 5))) + 1 \)
   
   - \( 2 \cdot ( (3 \cdot (4 \cdot 5)) + 1) \)
   
   - \( 2 \cdot ((3 \cdot 4) \cdot (5 + 1)) \)
   
   - \( 2 \cdot ((3 \cdot 4) \cdot ((5 + 1)) \cdot 5) \)
   
   - \( 2 \cdot ((3 \cdot 4) \cdot ((5 + 1) \cdot 5)) \)
   
   - \( ((2 \cdot 3) \cdot (4 \cdot (5 + 1))) + 1 \)
   
   - \( ((2 \cdot 3) \cdot ((4 \cdot 5) + 1)) + 1 \)
   
   - \( ((2 \cdot 3) \cdot ((4 \cdot 5) + 1)) \cdot 5 \)

### Conclusion:

By evaluating the expression for all possible placements of parentheses, we find that there are \( 14 \) distinct values that can be obtained. Therefore, the final answer is:

\[
\boxed{14}
\]
Correct Answer: 4
