What will come in place of question mark (? ) in the following number series ?
`48 " " 60 " " 90 " " 157.5 " " ? " " 787.5 `

Options

A. `315.50`
B. 305
C. 300
D. 315

Answer

To find the missing number in the series: `48, ?, 60, ?, 90, ?, 157.5, ?, ?, 787.5`, we will analyze the pattern in the series step by step.

1. **Identify the pattern**:
- The numbers seem to be increasing, and they appear to be multiplied by a certain factor at each step.

2. **Calculate the multipliers**:
- From 48 to 60:
\[ \frac{60}{48} = 1.25 \]
- From 60 to 90:
\[ \frac{90}{60} = 1.5 \]
- From 90 to 157.5:
\[ \frac{157.5}{90} = 1.75 \]

3. **Determine the missing multipliers**:
- It appears that the multipliers are increasing by 0.25 each time:
- 1.25 (for 48 to 60)
- 1.5 (for 60 to 90)
- 1.75 (for 90 to 157.5)
- Therefore, the multiplier for the number after 48 should be 1.25, and for the number after 60, it should be 1.5.

4. **Calculate the missing numbers**:
- The number after 48:
\[ 48 \times 1.25 = 60 \]
- The number after 60:
\[ 60 \times 1.5 = 90 \]
- The number after 90:
\[ 90 \times 1.75 = 157.5 \]

5. **Continuing the pattern**:
- The next multiplier after 1.75 would be 2.0:
\[ 157.5 \times 2 = 315 \]
- The next multiplier after 2.0 would be 2.5:
\[ 315 \times 2.5 = 787.5 \]

6. **Final answer**:
- The missing number in the series is **315**.