Three athletes competed in running. The first ran for 20 minutes at a speed of 12 km / h

Three athletes competed in running. The first ran for 20 minutes at a speed of 12 km / h, the second ran 5 km in half an hour, the third ran 6 km at a speed of 11 km / h. Who ran the fastest? Who has run the longer distance? Who ran the longest?

Given:

t1 = 20 minutes = 1200 seconds – the time of the first athlete’s race;

v1 = 12 km / h = 3.3 m / s – speed of the first athlete;

S2 = 5 kilometers = 5000 meters – distance run by the second athlete;

t2 = 30 minutes = 1800 seconds – run time of the second athlete;

S3 = 6 kilometers = 6000 meters – distance run by the third athlete;

v3 = 11 km / h = 3.1 m / s.

It is required to compare the speeds (v1, v2, v3) and the running time (t1, t2, t3) of athletes.

The running speed of the second athlete is:

v2 = S2 / t2 = 5000/1800 = 2.8 m / s.

Since v1> v2> v3 (3.3> 3.1> 2.8), the first athlete ran the fastest.

Race time of the third athlete:

t3 = S3 / v3 = 6000 / 3.1 = 1935 seconds.

Since t3> t2> t1 (1935> 1800> 1200), the third athlete ran the longest.

Answer: the first athlete ran the fastest, the third athlete ran the longest.