In each of the following questions a question is followed by information given in three statements. You have to study the question along with the statement and decide the information given in which of the statement (s) is necessary to answer the question.
What is the speed of the train ?
(1) Train crosses a pole is 240 seconds
(2) Length of the train is 240 metres
(3) Train crosses a platform of equal length in 20 seconds

Options

A. Only (1) and (2)
B. Only (2) and (3)
C. All (1),(2) and (3)
D. Any two of the three

Answer

To determine the speed of the train, we need to analyze the information provided in the statements.

### Step-by-Step Solution:

1. **Understanding Speed Formula**:
The speed of an object is calculated using the formula:
\[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} \]

2. **Analyzing Statement (1)**:
- **Statement**: Train crosses a pole in 240 seconds.
- **Analysis**: This statement alone does not provide the length of the train, so we cannot calculate the speed. We need more information.

3. **Analyzing Statement (2)**:
- **Statement**: Length of the train is 240 metres.
- **Analysis**: This statement gives us the length of the train, but without the time taken to cross a specific point (like a pole or platform), we still cannot calculate the speed.

4. **Analyzing Statement (3)**:
- **Statement**: Train crosses a platform of equal length in 20 seconds.
- **Analysis**: Here, the platform length is also 240 metres (same as the train length). When the train crosses the platform, it travels a distance equal to the length of the train plus the length of the platform:
\[ \text{Total Distance} = \text{Length of Train} + \text{Length of Platform} = 240 + 240 = 480 \text{ metres} \]
- The time taken to cross the platform is 20 seconds.

5. **Calculating Speed Using Statement (3)**:
\[ \text{Speed} = \frac{\text{Total Distance}}{\text{Time}} = \frac{480 \text{ metres}}{20 \text{ seconds}} = 24 \text{ m/s} \]

6. **Conclusion**:
- We find that to calculate the speed of the train, we need both the length of the train (Statement 2) and the time taken to cross the platform (Statement 3).
- Therefore, Statements (2) and (3) are necessary to answer the question.

### Final Answer:
The necessary statements to determine the speed of the train are **(2) and (3)**.