What should come in place of question mark in questions
18 9 9 18 72 ?

Options

A. 460
B. 372
C. 576
D. 484

Answer

To solve the problem, we need to identify the pattern in the given number series: 18, 9, 9, 18, 72, ?.

### Step-by-Step Solution:

1. **Identify the Sequence**: Write down the numbers in the series:
- 18, 9, 9, 18, 72, ?

2. **Analyze the Pattern**:
- The first number is 18.
- The second number is 9, which can be obtained by multiplying 18 by \( \frac{1}{2} \) (or dividing by 2).
- The third number is again 9, which remains the same as the second number.
- The fourth number is 18, which is obtained by multiplying the third number (9) by 2.
- The fifth number is 72, which is obtained by multiplying the fourth number (18) by 4.

3. **Establish the Multiplication Pattern**:
- The multipliers used so far are:
- From 18 to 9: \( \times \frac{1}{2} \)
- From 9 to 9: \( \times 1 \)
- From 9 to 18: \( \times 2 \)
- From 18 to 72: \( \times 4 \)

We can see that the multipliers are following a pattern: \( \frac{1}{2}, 1, 2, 4 \).

4. **Determine the Next Multiplier**:
- The next multiplier after 4 would be \( 8 \) (which is double of 4).

5. **Calculate the Next Number**:
- Multiply the last number (72) by the next multiplier (8):
\[ 72 \times 8 = 576 \]

6. **Conclusion**:
- The number that should come in place of the question mark is **576**.

### Final Answer:
The answer is **576**.