What will come in place of question mark (?) in the given numbers series ?
11 12 26 81 328 ?

Options

A. 1720
B. 1645
C. 1540
D. 1625

Answer

To solve the given number series: 11, 12, 26, 81, 328, ?, we will analyze the pattern in the series step by step.

### Step 1: Identify the pattern
Let's look at the series:
- The first number is 11.
- The second number is 12.
- The third number is 26.
- The fourth number is 81.
- The fifth number is 328.

### Step 2: Find the relationship between consecutive numbers
1. From 11 to 12:
- \( 11 \times 1 + 1 = 12 \)

2. From 12 to 26:
- \( 12 \times 2 + 2 = 26 \)

3. From 26 to 81:
- \( 26 \times 3 + 3 = 81 \)

4. From 81 to 328:
- \( 81 \times 4 + 4 = 328 \)

### Step 3: Apply the same pattern for the next number
Now, we will apply the same pattern to find the next number after 328:
- We will multiply 328 by 5 and then add 5.

Calculating:
- \( 328 \times 5 + 5 \)
- \( 1640 + 5 = 1645 \)

### Conclusion
The number that will come in place of the question mark (?) is **1645**.