23, 57, 40, 27, 51, 36

Options

A. 23
B. 36
C. 27
D. 51

Explanation

To solve the problem of identifying the odd number in the series 23, 57, 40, 27, 51, 36, we can follow these steps:

### Step 1: Group the numbers
We will group the numbers into pairs to find a pattern. The pairs will be (23, 57), (40, 27), and (51, 36).

### Step 2: Calculate the average of the first pair
For the first pair (23, 57):
- Calculate the average:
\[ \text{Average} = \frac{23 + 57}{2} = \frac{80}{2} = 40 \]
- The average is equal to the third number in the series, which is 40.

### Step 3: Calculate the average of the second pair
For the second pair (27, 51):
- Calculate the average:
\[ \text{Average} = \frac{27 + 51}{2} = \frac{78}{2} = 39 \]
- The average is 39, which does not equal the third number in this group, which is 36.

### Step 4: Identify the odd number
Since the average of the second pair (39) does not match the third number (36), we can conclude that 36 is the odd number in this series.

### Conclusion
The odd number in the series 23, 57, 40, 27, 51, 36 is **36**.

---