The bicycle pedist covered the distance between the two points at a speed of 21 km / h. He drove back at a speed three times slower.

The bicycle pedist covered the distance between the two points at a speed of 21 km / h. He drove back at a speed three times slower. What is the average speed along the way?

Let’s find the speed on the way back.
Because he was driving three times less, then we divide 21 km / h by 3
21 km / h / 3 = 7 km / h
To find the average speed, you need to find the arithmetic mean of the speeds
(21 km / h + 7 km / h) / 2 = 14 km / h
Answer: 14 km / h