Question

A cyclist covers first 5 kms at an average speed of 10 km per hour. Another 3 kms at an average
speed of 7 km per hour and the final 2 kms at an average speed of 3 km per hour. What is the average
speed for the entire journey?​

Answer 1

Given:

First Part:  5 km at 10 km/h

Second Part:  3 km at 7 km/h

Third Part: 2 km at 3 km/h

To Find:

Average speed for the whole journey

Solution:

Find the time taken for the first part of the journey:

Time = Distance ÷ Speed

Time = 5 ÷ 10 = 1/2 hour

Find the time taken for the second part of the journey:

Time = Distance ÷ Speed

Time = 3 ÷ 7 = 3/7 hour

Find the time taken for the third part of the journey:

Time = Distance ÷ Speed

Time = 2 ÷ 3 = 2/3 hour

Find the total time taken:

Total time taken = 1/2 + 3/7 + 2/3 = 67/42 hour

Find the total distance traveled:

Total distance = 5 + 3 + 2 = 10 km

Find the average speed for the whole journey:

Speed = Distance ÷ Time

Speed = 10 ÷ 67/42 = 6.27 km/h

Answer: The average speed is 6.27 km/h

Answer 2

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Refer to the attachment ❤️