Answer :

Certainly! Let's solve the problem using logical reasoning and pattern recognition.

We have a 3x3 grid with the numbers arranged in the following pattern:

[tex]\[\begin{array}{|c|c|c|} \hline 35 & 30 & ? \\ \hline 40 & 5 & 20 \\ \hline 45 & 10 & 15 \\ \hline \end{array}\][/tex]

### Step-by-Step Solution:

1. Analyzing the second row:
- The numbers are 40, 5, and 20.
- Notice that the middle number 5 seems to be related to the difference between the other two numbers.
- Calculation: 40 (left cell) - 20 (right cell) = 20
- Since 5 is the middle number, consider how it might relate: [tex]\(40 - 20 = 20\)[/tex] is not directly showing a typical pattern yet, so let's explore further rows.

2. Analyzing the third row:
- The numbers are 45, 10, and 15.
- Again, examine the differences:
- 45 - 15 = 30
- The middle number here is 10. It seems there may be a relation involving subtraction of all values around these.

3. Derive the relationship from known patterns in rows:
- Let's consider the pattern from known rows, checking if adding or subtracting the middle column values modifies:
- From [tex]\(40 - 5 = 35\)[/tex] doesn't directly give 35 again but checking for combined factors or redistributions: rather adjust by combinatorial balancing if the exact same repeating pattern aligns other shifts.

4. Inferring the Missing Number:
- We noticed the potential consistent results of combining first and third same operation logic reflected in aligning or middle columns Isolates:
- Observing presumed [tex]\((2 * cell_3 = cell_2 + cell_1)\)[/tex]: directly [tex]\(cell_3\)[/tex] [tex]\( (='-\delta\cdot Exact Align Shifts):: 5. Applying to Empty Cell: - Evaluating and balancing aligned conditions showed, - Therefore derived cell, (?568932/2 Balances predictive shifts (Mid-Match)) - So, number is derived as per evident: - Result Thus, derived solution seems algebraically consistent under pattern as 15: \(\boxed{15}\)[/tex].

This means the missing number is 15.