In a race, the average speed of a runner is 10 km/h. If he runs for 2 hours and
Practice Questions
Q1
In a race, the average speed of a runner is 10 km/h. If he runs for 2 hours and then walks for 1 hour at 5 km/h, what is his average speed for the entire journey?
8 km/h
9 km/h
10 km/h
11 km/h
Questions & Step-by-Step Solutions
In a race, the average speed of a runner is 10 km/h. If he runs for 2 hours and then walks for 1 hour at 5 km/h, what is his average speed for the entire journey?
Step 1: Identify the average speed of the runner while running, which is 10 km/h.
Step 2: Identify the time the runner spends running, which is 2 hours.
Step 3: Calculate the distance covered while running using the formula: Distance = Speed × Time. So, Distance = 10 km/h × 2 h = 20 km.
Step 4: Identify the average speed of the runner while walking, which is 5 km/h.
Step 5: Identify the time the runner spends walking, which is 1 hour.
Step 6: Calculate the distance covered while walking using the same formula: Distance = Speed × Time. So, Distance = 5 km/h × 1 h = 5 km.
Step 7: Add the distances from running and walking to find the total distance: Total Distance = 20 km + 5 km = 25 km.
Step 8: Add the total time spent running and walking to find the total time: Total Time = 2 h + 1 h = 3 h.
Step 9: Calculate the average speed for the entire journey using the formula: Average Speed = Total Distance / Total Time. So, Average Speed = 25 km / 3 h = 8.33 km/h.
