Tourists covered 8 km in 2 hours, then 4 km in 1.5 hours, and then, hurrying

Tourists covered 8 km in 2 hours, then 4 km in 1.5 hours, and then, hurrying to the train, ran 500 m in 240 seconds. What is the average tourist speed?

The solution of the problem:

S1 = 8 km

t1 = 2 h

S2 = 4 km

t2 = 1.5 h

S3 = 500 m

t3 = 240 s

For convenience, we will translate all distance values into kilometers, and all speed values into hours.

To convert meters to kilometers, you need to divide the value by 1000 (since 1000 m in 1 km)

S3 = 500 m = 0.5 km

To convert seconds to hours, you need to divide the value by 3600 (since in 1 hour there are 3600 s)

t3 = 240 s = 1/15 h

To calculate the average speed, you need to divide the sum of all distances by the sum of all time.

V = (S1 + S2 + S3) / (t1 + t2 + t3) = 12.5 / 3.567 = 3.5 (km / h)

Answer: 3.5 km / h