1, 2, 8, 15, 64, 128

Options

A. 198
B. 74
C. 15
D. 1

Explanation

To find the odd one out in the series: 1, 2, 8, 15, 64, 128, we will analyze the pattern of the numbers step by step.

### Step 1: Identify the pattern in the series
The given series is: 1, 2, 8, 15, 64, 128.

### Step 2: Check if the numbers are multiples of 2
- The first number is 1 (not a multiple of 2).
- The second number is 2 (a multiple of 2).
- The third number is 8 (a multiple of 2).
- The fourth number is 15 (not a multiple of 2).
- The fifth number is 64 (a multiple of 2).
- The sixth number is 128 (a multiple of 2).

### Step 3: Identify the odd one out
From the analysis, we can see that 15 is the only number that is not a multiple of 2. All other numbers in the series (1, 2, 8, 64, and 128) are either multiples of 2 or can be derived from powers of 2.

### Step 4: Conclusion
Thus, the odd one out in the series is **15**.

### Final Answer
The odd one out in the series is **15**.

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