Vipin crosses a 450 metre wide road in 9 seconds. What is his speed (in km/hr)?

Options

A. 195
B. 150
C. 210
D. 180

Answer

To find Vipin's speed in kilometers per hour after crossing a 450-meter wide road in 9 seconds, we can follow these steps:

### Step 1: Calculate Speed in Meters per Second
First, we need to calculate Vipin's speed in meters per second (m/s). The formula for speed is:

\[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} \]

Given:
- Distance = 450 meters
- Time = 9 seconds

Now, substituting the values into the formula:

\[ \text{Speed} = \frac{450 \text{ meters}}{9 \text{ seconds}} = 50 \text{ m/s} \]

### Step 2: Convert Speed to Kilometers per Hour
Next, we need to convert the speed from meters per second to kilometers per hour. The conversion factors are:
- 1 kilometer = 1000 meters
- 1 hour = 3600 seconds

To convert from m/s to km/hr, we use the following relationship:

\[ \text{Speed (km/hr)} = \text{Speed (m/s)} \times \frac{3600 \text{ seconds}}{1000 \text{ meters}} \]

Now substituting the speed we calculated:

\[ \text{Speed (km/hr)} = 50 \text{ m/s} \times \frac{3600}{1000} \]

Calculating the conversion:

\[ \text{Speed (km/hr)} = 50 \text{ m/s} \times 3.6 = 180 \text{ km/hr} \]

### Final Answer
Vipin's speed is **180 km/hr**.

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