What should come in place of the question mark (?) in the following number series ?
`20" "15" "20" "45" "160" "?`

Options

A. 775
B. 800
C. 575
D. 885

Answer

To solve the number series question: `20, 15, 20, 45, 160, ?`, we will analyze the pattern step by step.

### Step 1: Identify the pattern between the numbers
Let's write down the series again:
- 20
- 15
- 20
- 45
- 160

### Step 2: Calculate how to get from one number to the next
1. From **20 to 15**:
- We can see that \( 20 \times 1 - 5 = 15 \).

2. From **15 to 20**:
- Here, \( 15 \times 2 - 10 = 20 \).

3. From **20 to 45**:
- We can calculate \( 20 \times 3 - 15 = 45 \).

4. From **45 to 160**:
- This can be calculated as \( 45 \times 4 - 20 = 160 \).

### Step 3: Determine the next number in the series
Now, we need to find the next number after 160:
- Following the pattern, we multiply by 5 and then subtract 25:
- \( 160 \times 5 - 25 \)

### Step 4: Perform the calculation
1. Calculate \( 160 \times 5 = 800 \).
2. Now subtract 25:
- \( 800 - 25 = 775 \).

### Conclusion
Thus, the number that should come in place of the question mark (?) is **775**.

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