999, 730, 511, 344, 215, ….

Options

A. 123
B. 126
C. 125
D. 130

Explanation

To find the next number in the series: 999, 730, 511, 344, 215, …, we need to identify the pattern in the series.

### Step 1: Identify the pattern
Let's analyze the numbers in the series:

1. The first number is 999.
2. The second number is 730.
3. The third number is 511.
4. The fourth number is 344.
5. The fifth number is 215.

### Step 2: Calculate the differences between consecutive terms
Now, let's find the differences between each pair of consecutive terms:

- Difference between 999 and 730:
\( 999 - 730 = 269 \)

- Difference between 730 and 511:
\( 730 - 511 = 219 \)

- Difference between 511 and 344:
\( 511 - 344 = 167 \)

- Difference between 344 and 215:
\( 344 - 215 = 129 \)

So, the differences are:
- 269
- 219
- 167
- 129

### Step 3: Identify the pattern in the differences
Now, let's look at the differences:
- The first difference is 269.
- The second difference is 219.
- The third difference is 167.
- The fourth difference is 129.

Now, let's find the differences of these differences:
- Difference between 269 and 219:
\( 269 - 219 = 50 \)

- Difference between 219 and 167:
\( 219 - 167 = 52 \)

- Difference between 167 and 129:
\( 167 - 129 = 38 \)

### Step 4: Predict the next difference
The differences of the differences seem to be decreasing, but not in a consistent manner. However, we can see that the differences are decreasing.

If we look at the last difference (129), we can estimate that the next difference could be around 100 (as it seems to be decreasing).

### Step 5: Calculate the next number
If we assume the next difference is 100, we can calculate the next term in the series:
- Last number in the series is 215.
- If we subtract 100 from 215:
\( 215 - 100 = 115 \)

### Conclusion
Thus, the next number in the series is **115**.