KCC's quiz AQQ274 about 2 sportsmen running and walking

This is a nice easy problem as the only thing you need to know is

Distance = Speed x Time   D=S.T

For starters, let’s assume walking is 5 km/h and running is 10 km/h, and their distance is 10 km.

Take the case of Sportsman A walking and running each for half of the time:

T/2 x 10   +    T/2 x 5  = 10

So 7.5T = 10, the time to complete the course is 10/7.5 = 1.33 hours.

In the other case - Sportsman B - we need 2 times, T1 and T2:

T1 x 10 = 5   so T1 must be 0.5 hours

T2 x 5 = 5      so T2 must be 1 hour

Total time is thus 1.5 hours.

So it is better to run and walk each for half of the time - ie B will be faster.

A bit of work with Excel confirmed that as long as the running speed is more than the walking speed, this strategy will work, as long as Sportsman B knows his walking and running speeds, and can do the math and can calculate the times he has to run and walk!

This is a nice easy problem as the only thing you need to know is

Distance = Speed x Time   D=S.T

For starters, let’s assume walking is 5 km/h and running is 10 km/h, and their distance is 10 km.

Take the case of Sportsman A walking and running each for half of the time:

T/2 x 10   +    T/2 x 5  = 10

So 7.5T = 10, the time to complete the course is 10/7.5 = 1.33 hours.

In the other case - Sportsman B - we need 2 times, T1 and T2:

T1 x 10 = 5   so T1 must be 0.5 hours

T2 x 5 = 5      so T2 must be 1 hour

Total time is thus 1.5 hours.

So it is better to run and walk each for half of the time - ie B will be faster.

A bit of work with Excel confirmed that as long as the running speed is more than the walking speed, this strategy will work, as long as Sportsman B knows his walking and running speeds, and can do the math and can calculate the times he has to run and walk!

Bravo @dash, you get it!