What will come in place of question mark (?) in the given question?
8 9 17 26 90 ?

Options

A. 121
B. 109
C. 115
D. 125

Answer

To solve the problem, we need to identify the pattern in the given series: 8, 9, 17, 26, 90, ?

### Step-by-Step Solution:

1. **Identify the Sequence**: The numbers in the sequence are 8, 9, 17, 26, 90. We need to find the next number in this series.

2. **Calculate the Differences**:
- First, find the difference between consecutive terms:
- 9 - 8 = 1
- 17 - 9 = 8
- 26 - 17 = 9
- 90 - 26 = 64

So, the differences are: 1, 8, 9, 64.

3. **Identify the Pattern in Differences**:
- Now, let's analyze the differences:
- The first difference is 1 (which is \(1^2\)).
- The second difference is 8 (which is \(2^3\)).
- The third difference is 9 (which is \(3^2\)).
- The fourth difference is 64 (which is \(4^3\)).

The pattern alternates between squares and cubes:
- \(1^2\), \(2^3\), \(3^2\), \(4^3\).

4. **Continue the Pattern**:
- Following this pattern, the next difference should be \(5^2\), which is 25.

5. **Add the Next Difference**:
- Now, add this difference (25) to the last term in the series (90):
- 90 + 25 = 115.

6. **Final Answer**:
- Therefore, the number that comes in place of the question mark (?) is **115**.