What should come in place of question mark (?) in the following questions.
5,15,45,135,?,1215

Options

A. A)415
B. B)395
C. C)410
D. D)405

Answer

To solve the question, we need to identify the pattern in the given series: 5, 15, 45, 135, ?, 1215.

### Step-by-Step Solution:

1. **Identify the Series**: The series given is:
- 1st term: 5
- 2nd term: 15
- 3rd term: 45
- 4th term: 135
- 5th term: ?
- 6th term: 1215

2. **Find the Pattern**: Let's look at how each term relates to the previous term:
- From 5 to 15: \( 5 \times 3 = 15 \)
- From 15 to 45: \( 15 \times 3 = 45 \)
- From 45 to 135: \( 45 \times 3 = 135 \)

We can see that each term is obtained by multiplying the previous term by 3.

3. **Calculate the Missing Term**: Now, we can find the missing term (5th term) by multiplying the 4th term (135) by 3:
\[ ? = 135 \times 3 \]
\[ ? = 405 \]

4. **Verify the Next Term**: To ensure our answer is correct, we can check if multiplying the 5th term (405) by 3 gives us the 6th term (1215):
\[ 405 \times 3 = 1215 \]
This confirms that our calculation is correct.

5. **Final Answer**: The missing term in the series is 405.

### Summary:
The missing number in the series is **405**.

---