Direction: In the following number series question one number is wrong. Find out the wrong number.
391 394 399 411 431 461 503

Options

A. 399
B. 411
C. 394
D. 461

Answer

To find the wrong number in the series: 391, 394, 399, 411, 431, 461, 503, we will analyze the differences between the consecutive numbers and identify any inconsistencies.

### Step-by-Step Solution:

1. **Identify the series**:
The given series is:
- 391, 394, 399, 411, 431, 461, 503

2. **Calculate the differences between consecutive numbers**:
- 394 - 391 = 3
- 399 - 394 = 5
- 411 - 399 = 12
- 431 - 411 = 20
- 461 - 431 = 30
- 503 - 461 = 42

So, the differences are:
- 3, 5, 12, 20, 30, 42

3. **Look for a pattern in the differences**:
The differences do not seem to follow a simple arithmetic progression. Let's analyze them further:
- The difference between the first two differences (3 and 5) is 2.
- The difference between the next pair (5 and 12) is 7.
- The difference between (12 and 20) is 8.
- The difference between (20 and 30) is 10.
- The difference between (30 and 42) is 12.

This suggests that the differences are increasing, but not consistently.

4. **Re-evaluate the numbers**:
Let's try to see if we can find a consistent pattern:
- If we assume the first difference should be 2, then:
- 391 + 2 = 393
- 393 + 6 = 399
- 399 + 12 = 411
- 411 + 20 = 431
- 431 + 30 = 461
- 461 + 42 = 503

5. **Identify the wrong number**:
If we replace 394 with 393, we can see that the series would then follow a consistent pattern:
- 391 + 2 = 393
- 393 + 6 = 399
- 399 + 12 = 411
- 411 + 20 = 431
- 431 + 30 = 461
- 461 + 42 = 503

Therefore, the wrong number in the series is **394**.

### Conclusion:
The wrong number in the series is **394**.