If a runner completes a 10 km race in 40 minutes, what is his average speed in k

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Question: If a runner completes a 10 km race in 40 minutes, what is his average speed in km/h? (2021)

Options:

Correct Answer: 14 km/h

Exam Year: 2021

Solution:

Time = 40 minutes = 40/60 hours = 2/3 hours. Speed = Distance / Time = 10 km / (2/3) hours = 10 * (3/2) = 15 km/h.

If a runner completes a 10 km race in 40 minutes, what is his average speed in km/h? (2021)

If a runner completes a 10 km race in 40 minutes, what is his average speed in km/h? (2021)

Step 1: Understand that the runner completed a distance of 10 kilometers.
Step 2: Convert the time from minutes to hours. Since there are 60 minutes in an hour, divide 40 minutes by 60. This gives you 40/60 hours.
Step 3: Simplify 40/60 to get 2/3 hours.
Step 4: Use the formula for speed, which is Speed = Distance / Time.
Step 5: Plug in the values: Distance is 10 km and Time is 2/3 hours.
Step 6: To divide by a fraction (2/3), you multiply by its reciprocal. So, 10 km / (2/3) hours is the same as 10 km * (3/2).
Step 7: Calculate 10 * (3/2) to find the speed. This equals 15 km/h.

Average Speed Calculation – The average speed is calculated by dividing the total distance traveled by the total time taken, requiring conversion of time units when necessary.
Unit Conversion – Understanding how to convert minutes to hours is essential for calculating speed in km/h.