The following number series only one number is wrong . Find out the wrong number
`850 " "600" "550" "500" "475" "462.5" "456.25`

Options

A. 600
B. 550
C. 500
D. 462.5

Answer

To find the wrong number in the series `850, 600, 550, 500, 475, 462.5, 456.25`, we can analyze the pattern of the differences between the numbers.

### Step-by-Step Solution:

1. **Identify the Series**: The given series is:
```
850, 600, 550, 500, 475, 462.5, 456.25
```

2. **Calculate the Differences**: Let's calculate the differences between consecutive numbers:
- \( 850 - 600 = 250 \)
- \( 600 - 550 = 50 \)
- \( 550 - 500 = 50 \)
- \( 500 - 475 = 25 \)
- \( 475 - 462.5 = 12.5 \)
- \( 462.5 - 456.25 = 6.25 \)

So, the differences are:
```
250, 50, 50, 25, 12.5, 6.25
```

3. **Analyze the Pattern**: The differences seem to be halving:
- The first difference is \( 250 \).
- The second difference is \( 50 \) (which is \( 250 / 5 \)).
- The third difference is also \( 50 \) (this is consistent).
- The fourth difference is \( 25 \) (which is \( 50 / 2 \)).
- The fifth difference is \( 12.5 \) (which is \( 25 / 2 \)).
- The sixth difference is \( 6.25 \) (which is \( 12.5 / 2 \)).

4. **Identify the Anomaly**: The pattern indicates that after \( 250 \), the next difference should have been \( 100 \) (which is half of \( 250 \)). However, we see \( 600 \) instead of \( 650 \) (which would be \( 850 - 100 \)).

5. **Conclusion**: The wrong number in the series is \( 600 \). It should be \( 650 \) to maintain the pattern of halving the differences.

### Final Answer:
The wrong number in the series is **600**.