A bus travels 720 km in 10 hours. Calculate its average speed in meters/second.

Options

A. 12
B. 15
C. 18
D. 20

Answer

To find the average speed of the bus in meters per second, we will follow these steps:

### Step 1: Identify the given values
- Total distance traveled by the bus = 720 km
- Total time taken = 10 hours

### Step 2: Convert distance from kilometers to meters
To convert kilometers to meters, we use the conversion factor:
1 km = 1000 meters

So, we convert 720 km to meters:
\[ \text{Distance in meters} = 720 \, \text{km} \times 1000 \, \text{m/km} = 720000 \, \text{m} \]

### Step 3: Convert time from hours to seconds
To convert hours to seconds, we use the conversion factors:
1 hour = 60 minutes
1 minute = 60 seconds

Thus, 1 hour = 60 minutes × 60 seconds/minute = 3600 seconds.

Now, we convert 10 hours to seconds:
\[ \text{Time in seconds} = 10 \, \text{hours} \times 3600 \, \text{s/hour} = 36000 \, \text{s} \]

### Step 4: Calculate average speed
Average speed is calculated using the formula:
\[ \text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}} \]

Substituting the values we found:
\[ \text{Average Speed} = \frac{720000 \, \text{m}}{36000 \, \text{s}} \]

### Step 5: Simplify the calculation
Now, we simplify the fraction:
\[ \text{Average Speed} = \frac{720000}{36000} = 20 \, \text{m/s} \]

### Final Answer
The average speed of the bus is **20 meters per second**.

---