What value will come in place of question mark (?) in the number-series given below?
17 306 ? 380 21 462

Options

A. 20
B. 18
C. 19
D. 22

Answer

To solve the given number series: 17, 306, ?, 380, 21, 462, we need to identify the pattern connecting these numbers.

### Step-by-Step Solution:

1. **Identify the Numbers in the Series**:
The series is: 17, 306, ?, 380, 21, 462.

2. **Look for Patterns**:
We can observe that the numbers seem to alternate between two types of values: single-digit numbers (17, ?, 21) and larger numbers (306, 380, 462).

3. **Analyze the Single-Digit Numbers**:
The single-digit numbers are: 17, ?, and 21. It appears that they are increasing. If we assume the missing number is between 17 and 21, it could logically be 18, 19, or 20.

4. **Examine the Larger Numbers**:
The larger numbers are: 306, 380, and 462. Let's look at the differences between these numbers:
- 380 - 306 = 74
- 462 - 380 = 82

5. **Check the Relationship**:
Now, let's check if there's a relationship between the larger numbers and the single-digit numbers:
- If we take 306 and divide it by 17 (the first single-digit number), we get:
\[ 306 ÷ 17 = 18 \]
- If we take 380 and divide it by 19 (the next possible single-digit number), we get:
\[ 380 ÷ 20 = 19 \]
- If we take 462 and divide it by 21 (the last single-digit number), we get:
\[ 462 ÷ 22 = 21 \]

6. **Determine the Missing Value**:
Following this pattern, the missing value that fits the series is 19, as it is the number that fits logically between 18 (from 306) and 20 (from 380).

### Conclusion:
The value that will come in place of the question mark (?) is **19**.