4,9,19,39,79,160,319

Options

A. 319
B. 160
C. 79
D. 39

Answer

To identify the odd number out of the series 4, 9, 19, 39, 79, 160, 319, we can analyze the differences between consecutive terms and look for a pattern.

### Step-by-Step Solution:

1. **List the series**:
- The series is: 4, 9, 19, 39, 79, 160, 319.

2. **Calculate the differences between consecutive terms**:
- 9 - 4 = 5
- 19 - 9 = 10
- 39 - 19 = 20
- 79 - 39 = 40
- 160 - 79 = 81
- 319 - 160 = 159

So, the differences are: 5, 10, 20, 40, 81, 159.

3. **Analyze the differences**:
- The differences seem to follow a pattern initially: 5, 10, 20, 40 (which doubles each time).
- However, the next difference is 81, which does not fit the doubling pattern (it should be 80).
- The last difference is 159, which also does not fit the pattern.

4. **Identify the odd number**:
- The difference of 81 (between 79 and 160) is the first deviation from the expected pattern of doubling differences (5, 10, 20, 40, 80).
- Therefore, 160 is the odd number out as it disrupts the established pattern.

5. **Conclusion**:
- The odd number out in the series is **160**.