3600 725 150 35 12 ?

Options

A. 8
B. 7.4
C. 10.5
D. 10

Explanation

To find the missing number in the series: 3600, 725, 150, 35, 12, ?, we will analyze the pattern step by step.

### Step 1: Identify the pattern
We start with the first two numbers: 3600 and 725. We can see that the numbers are decreasing significantly. Let's look for a pattern in how they are related.

### Step 2: Calculate the first operation
To go from 3600 to 725, we can divide 3600 by 5:
\[ 3600 \div 5 = 720 \]
Then, we add 5 to 720:
\[ 720 + 5 = 725 \]

### Step 3: Calculate the second operation
Next, we go from 725 to 150. Again, we divide by 5:
\[ 725 \div 5 = 145 \]
Then, we add 5:
\[ 145 + 5 = 150 \]

### Step 4: Calculate the third operation
Now, we move from 150 to 35. We divide 150 by 5:
\[ 150 \div 5 = 30 \]
Then, we add 5:
\[ 30 + 5 = 35 \]

### Step 5: Calculate the fourth operation
Next, we go from 35 to 12. We divide 35 by 5:
\[ 35 \div 5 = 7 \]
Then, we add 5:
\[ 7 + 5 = 12 \]

### Step 6: Calculate the missing number
Now we need to find the missing number after 12. We divide 12 by 5:
\[ 12 \div 5 = 2.4 \]
Then, we add 5:
\[ 2.4 + 5 = 7.4 \]

### Conclusion
Thus, the missing number in the series is **7.4**.