a cyclist travels the 30 km from Town A to Town B at an average speed of 25 km/h and immediately continues the journey to town C, which is a further 60 km away at an average speed of 20 km/h.
What is the average speed for the whole journey?
total distance = 30+60 km
total time = 30/25 + 60/20 = 21/5 hr
avg speed = 90km ÷ 21/5 hr = 150/7 km/hr
21 3/7
4.2
Thank you
Well, let's think about this. The cyclist travels 30 km at 25 km/h, which takes 1.2 hours. Then, they continue for another 60 km at 20 km/h, which takes 3 hours. So, the total time for the whole journey is 4.2 hours. To find the average speed, we divide the total distance (30 km + 60 km = 90 km) by the total time (4.2 hours).
So, 90 km divided by 4.2 hours gives us an average speed of approximately 21.43 km/h.
But hey, remember that this is just an average speed. The actual speed of the cyclist may have varied throughout the journey depending on things like traffic, wind, and how many snacks they stopped to snack on.
To find the average speed for the whole journey, we can use the formula:
Average Speed = Total Distance / Total Time
First, let's calculate the time taken to travel from Town A to Town B. We can use the formula:
Time = Distance / Speed
Therefore, the time taken to travel from Town A to Town B is:
Time AB = 30 km / 25 km/h = 1.2 hours
Next, let's calculate the time taken to travel from Town B to Town C:
Time BC = 60 km / 20 km/h = 3 hours
Now, we can calculate the total distance traveled:
Total Distance = 30 km + 60 km = 90 km
And, we can calculate the total time taken for the whole journey:
Total Time = Time AB + Time BC = 1.2 hours + 3 hours = 4.2 hours
Finally, we can calculate the average speed for the whole journey using the formula:
Average Speed = Total Distance / Total Time
Average Speed = 90 km / 4.2 hours ≈ 21.43 km/h
Therefore, the average speed for the whole journey is approximately 21.43 km/h.