What will come in place of questions mark (?) in the following number series ?
`"18 34 66 114 178 ?"`

Options

A. 252
B. 258
C. 242
D. 285

Answer

To find the missing number in the series "18, 34, 66, 114, 178, ?", we can start by examining the differences between consecutive terms.

1. **Calculate the differences between consecutive terms:**
- 34 - 18 = 16
- 66 - 34 = 32
- 114 - 66 = 48
- 178 - 114 = 64

So, the differences are: 16, 32, 48, 64.

2. **Calculate the differences of the differences:**
- 32 - 16 = 16
- 48 - 32 = 16
- 64 - 48 = 16

The second differences are constant and equal to 16.

3. **Predict the next difference:**
Since the second differences are constant, we can predict that the next difference will also be 64 + 16 = 80.

4. **Add the predicted difference to the last term in the series:**
- 178 + 80 = 258.

Thus, the number that will come in place of the question mark (?) is **258**.