What will come in place of the question mark (?) in the following number series +?
101 103 109 121 141 ?

Options

A. 154
B. 198
C. 166
D. 171

Answer

To solve the number series question, we need to identify the pattern in the differences between the consecutive numbers in the series: 101, 103, 109, 121, 141, ?.

### Step-by-Step Solution:

1. **List the numbers in the series**:
- The series is: 101, 103, 109, 121, 141, ?

2. **Calculate the differences between consecutive numbers**:
- Difference between 103 and 101:
\[ 103 - 101 = 2 \]
- Difference between 109 and 103:
\[ 109 - 103 = 6 \]
- Difference between 121 and 109:
\[ 121 - 109 = 12 \]
- Difference between 141 and 121:
\[ 141 - 121 = 20 \]

So, the differences are: 2, 6, 12, 20.

3. **Identify the pattern in the differences**:
- The differences are increasing:
- From 2 to 6, the increase is 4.
- From 6 to 12, the increase is 6.
- From 12 to 20, the increase is 8.
- The pattern in the increases appears to be increasing by 2 each time:
- 4 (2+2), 6 (4+2), 8 (6+2).

4. **Predict the next difference**:
- Following the pattern, the next increase should be:
\[ 20 + 10 = 30 \]

5. **Calculate the next number in the series**:
- Add the predicted difference (30) to the last number in the series (141):
\[ 141 + 30 = 171 \]

6. **Conclusion**:
- Therefore, the number that will come in place of the question mark (?) is **171**.

### Final Answer:
**171**