Find the wrong number in the following number series.
36,80,166,340,690,1392,2798

Options

A. A)690
B. B)36
C. C)340
D. D)1392

Answer

To find the wrong number in the series 36, 80, 166, 340, 690, 1392, 2798, we will analyze the pattern in the series step by step.

### Step 1: Identify the Pattern
We will look at how each term relates to the previous term.

1. **From 36 to 80**:
- We can observe that if we add 4 to 36 and then multiply by 2, we get:
\[ (36 + 4) \times 2 = 40 \times 2 = 80 \]

2. **From 80 to 166**:
- Now, we add 3 to 80 and multiply by 2:
\[ (80 + 3) \times 2 = 83 \times 2 = 166 \]

3. **From 166 to 340**:
- Next, we add 4 to 166 and multiply by 2:
\[ (166 + 4) \times 2 = 170 \times 2 = 340 \]

4. **From 340 to 690**:
- Here, we add 5 to 340 and multiply by 2:
\[ (340 + 5) \times 2 = 345 \times 2 = 690 \]

5. **From 690 to 1392**:
- We add 6 to 690 and multiply by 2:
\[ (690 + 6) \times 2 = 696 \times 2 = 1392 \]

6. **From 1392 to 2798**:
- Finally, we add 7 to 1392 and multiply by 2:
\[ (1392 + 7) \times 2 = 1399 \times 2 = 2798 \]

### Step 2: Check for Consistency
Now, let's summarize the additions:
- From 36 to 80: added 4
- From 80 to 166: added 3
- From 166 to 340: added 4
- From 340 to 690: added 5
- From 690 to 1392: added 6
- From 1392 to 2798: added 7

### Step 3: Identify the Wrong Number
The pattern of additions seems to be inconsistent. If we look closely:
- The first term should have been derived by adding 4 to 36 and then multiplying by 2, which gives us 80.
- However, if we look at the pattern of additions, it should have started from 38 (which is 36 + 2) to maintain the sequence.

Thus, the first term should be 38 instead of 36.

### Conclusion
The wrong number in the series is **36**.