0.5, 0.55, 0.65, 0.8, ?

Options

A. 0.9
B. 0.82
C. 1
D. 0.95

Explanation

To solve the series: 0.5, 0.55, 0.65, 0.8, ?, we will analyze the differences between the consecutive terms and identify the pattern.

### Step-by-Step Solution:

1. **Identify the Terms**: The given series is 0.5, 0.55, 0.65, 0.8.

2. **Calculate the Differences**:
- The difference between the first term (0.5) and the second term (0.55) is:
\[ 0.55 - 0.5 = 0.05 \]
- The difference between the second term (0.55) and the third term (0.65) is:
\[ 0.65 - 0.55 = 0.10 \]
- The difference between the third term (0.65) and the fourth term (0.8) is:
\[ 0.8 - 0.65 = 0.15 \]

3. **Observe the Pattern in Differences**:
- The differences we calculated are:
- 0.05 (between 0.5 and 0.55)
- 0.10 (between 0.55 and 0.65)
- 0.15 (between 0.65 and 0.8)
- We can see that the differences are increasing by 0.05 each time.

4. **Predict the Next Difference**:
- Following the pattern, the next difference should be:
\[ 0.15 + 0.05 = 0.20 \]

5. **Calculate the Next Term**:
- To find the next term in the series, we add this difference (0.20) to the last known term (0.8):
\[ 0.8 + 0.20 = 1.0 \]

6. **Conclusion**:
- Therefore, the next number in the series is **1.0**.

### Final Answer:
The missing number in the series is **1.0**.