A runner wants to run 13.1 km . She knows that her running pace is 6.2 mi/h .How many minutes must she run?
The correct answer and explanation is:
To find out how many minutes the runner must run to complete 13.1 kilometers at a pace of 6.2 miles per hour, the following steps are needed:
- Convert the distance from kilometers to miles since the pace is given in miles per hour.
- Calculate the time in hours by dividing the distance in miles by the pace in miles per hour.
- Convert the time from hours to minutes.
Step 1: Convert 13.1 kilometers to miles.
1 kilometer is approximately 0.621371 miles.
So, 13.1 km × 0.621371 = 8.144 miles (rounded to three decimal places).
Step 2: Calculate the time in hours.
Time = Distance ÷ Speed
Time = 8.144 miles ÷ 6.2 miles per hour ≈ 1.3145 hours.
Step 3: Convert hours to minutes.
1 hour = 60 minutes
So, 1.3145 hours × 60 minutes/hour ≈ 78.87 minutes.
Therefore, the runner must run for approximately 79 minutes to complete 13.1 kilometers at a pace of 6.2 miles per hour.
Explanation:
This problem involves converting units and applying the basic formula for time, which is time equals distance divided by speed. The key challenge is dealing with different units: the distance is in kilometers while the speed is in miles per hour. To ensure consistency, the distance must be converted into miles. The conversion factor between kilometers and miles is crucial for this step. After conversion, dividing the total miles by the pace gives the time in hours. Since the question asks for the time in minutes, the hours are then converted to minutes by multiplying by 60.
This process is typical in many real-world problems where units differ. Proper conversion is necessary to avoid incorrect answers. The rounding here is done after the final step to keep the answer as precise as needed. Using this method ensures the runner’s time to complete the 13.1 km distance at the given pace is calculated accurately and practically.