Find out the wrong number in the series
190 166 145 128 112 100 91

Options

A. 100
B. 166
C. 145
D. 128

Answer

To find the wrong number in the series 190, 166, 145, 128, 112, 100, 91, we will analyze the differences between consecutive terms.

### Step-by-step Solution:

1. **Identify the series**: The series given is:
\[ 190, 166, 145, 128, 112, 100, 91 \]

2. **Calculate the differences between consecutive terms**:
- Difference between 190 and 166:
\[ 190 - 166 = 24 \]
- Difference between 166 and 145:
\[ 166 - 145 = 21 \]
- Difference between 145 and 128:
\[ 145 - 128 = 17 \]
- Difference between 128 and 112:
\[ 128 - 112 = 16 \]
- Difference between 112 and 100:
\[ 112 - 100 = 12 \]
- Difference between 100 and 91:
\[ 100 - 91 = 9 \]

3. **List the differences**:
The differences we calculated are:
\[ 24, 21, 17, 16, 12, 9 \]

4. **Analyze the pattern of differences**:
- The differences seem to decrease, but not consistently. Let's look at the differences:
- From 24 to 21, the difference is 3.
- From 21 to 17, the difference is 4.
- From 17 to 16, the difference is 1.
- From 16 to 12, the difference is 4.
- From 12 to 9, the difference is 3.

5. **Identify the inconsistency**:
- The expected pattern in the differences should ideally decrease by a consistent amount. The differences should follow a pattern of decreasing by 3, which is not happening here.
- The jump from 21 to 17 (a decrease of 4) seems to be the anomaly.

6. **Determine the correct number**:
- If we assume the difference should consistently decrease by 3, starting from 24:
- The next difference after 24 should be 21 (which is correct).
- The next difference should be 18 (not 17).
- Therefore, instead of 128, we should have:
\[ 145 - 18 = 127 \]

7. **Conclusion**:
- The wrong number in the series is **128**. The correct number should be **127**.