What will come in place of the questions mark (?) in the following number series ?
`40320,20160,6720,?,336`

Options

A. 1680
B. 1580
C. 1780
D. 1820

Answer

To find the missing number in the series `40320, 20160, 6720, ?, 336`, we can observe the pattern in the series.

### Step-by-Step Solution:

1. **Identify the Pattern**:
- The first number is `40320`.
- The second number is `20160`.
- The third number is `6720`.
- We need to find the fourth number, and the fifth number is `336`.

2. **Calculate the Division**:
- From `40320` to `20160`, we can see that:
\[ 40320 \div 2 = 20160 \]
- From `20160` to `6720`, we can see that:
\[ 20160 \div 3 = 6720 \]

3. **Continue the Pattern**:
- Following the pattern, the next step would be to divide by `4`:
\[ 6720 \div 4 = ? \]

4. **Perform the Division**:
- Now, we calculate:
\[ 6720 \div 4 = 1680 \]

5. **Verify the Next Step**:
- To confirm our answer, we can check if dividing `1680` by `5` gives us `336`:
\[ 1680 \div 5 = 336 \]
- This confirms that our calculations are correct.

### Conclusion:
The missing number in the series is **1680**.