Find the wrong number in series
`39,38,34,24,9,?`

Options

A. 9
B. 34
C. 24
D. 38

Answer

To find the wrong number in the series `39, 38, 34, 24, 9, ?`, we will analyze the pattern in the sequence step by step.

### Step-by-Step Solution:

1. **Identify the series**: The series given is `39, 38, 34, 24, 9`.

2. **Calculate the differences**:
- From `39` to `38`:
\[ 39 - 38 = 1 \]
- From `38` to `34`:
\[ 38 - 34 = 4 \]
- From `34` to `24`:
\[ 34 - 24 = 10 \]
- From `24` to `9`:
\[ 24 - 9 = 15 \]

3. **Analyze the differences**: The differences are `1, 4, 10, 15`. Let's look for a pattern in these differences:
- The first difference is \(1 = 1^2\)
- The second difference is \(4 = 2^2\)
- The third difference is \(9 = 3^2\) (but we have \(10\) here)
- The fourth difference is \(16 = 4^2\) (but we have \(15\) here)

4. **Identify the expected value**:
- According to the pattern, after `34`, we should subtract \(9\) (which is \(3^2\)) to get \(25\) instead of \(24\).
- Therefore, the correct sequence should be:
- \(39\) (first term)
- \(39 - 1 = 38\) (second term)
- \(38 - 4 = 34\) (third term)
- \(34 - 9 = 25\) (fourth term)
- \(25 - 16 = 9\) (fifth term)

5. **Conclusion**: The number `24` in the series is incorrect. It should be `25`.

### Final Answer:
The wrong number in the series is **24**.

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