Find the value of (?) in the following number series.
`3.5," "2.5," "3," "6," "20," "?`

Options

A. A)95
B. B)80
C. C)65
D. D)75

Answer

To find the value of (?) in the number series `3.5, 2.5, 3, 6, 20, ?`, we can analyze the pattern in the series step by step.

### Step-by-Step Solution:

1. **Identify the Terms**: The series is given as:
- First term (T1) = 3.5
- Second term (T2) = 2.5
- Third term (T3) = 3
- Fourth term (T4) = 6
- Fifth term (T5) = 20
- Sixth term (T6) = ?

2. **Analyze the Pattern**:
- From T1 to T2:
- \( T2 = T1 - 1 = 3.5 - 1 = 2.5 \)
- From T2 to T3:
- \( T3 = T2 + 0.5 = 2.5 + 0.5 = 3 \)
- From T3 to T4:
- \( T4 = T3 \times 2 = 3 \times 2 = 6 \)
- From T4 to T5:
- \( T5 = T4 \times \frac{10}{3} = 6 \times \frac{10}{3} = 20 \)

3. **Establish the Next Term**:
- We can see a multiplication pattern emerging:
- The first operation was a subtraction, the second was an addition, and the next two were multiplications.
- Continuing this pattern, we can hypothesize that the next term (T6) will involve multiplying T5 by 5:
- \( T6 = T5 \times 5 = 20 \times 5 = 100 \)

4. **Final Answer**:
- Therefore, the value of (?) is 100.

### Summary:
The missing term in the series is **100**.