Question

Kenyan Eliud Kipchoge set a new world record for men of 2:01:39 on September 16, 2018. Assign his average speed in km/h to the variable marathon. The marathon distance is 42.195 kilometers.

Answer 1

Given:

(i) Eliud Kipchoge ran the 42.195 km marathon in 2:01:39.

To find:

(i) His average speed in km/h.

Solution:

As given, the total marathon distance (D) is = 42.195km

Time taken is (T) = 2:01:39

The time is simplified as 2 hours 1 minute and 39 seconds.

As 1 hour = 60 minutes = (60*60)s = 3600s

So, 2 hours mean = 2*3600s = 7200s

1 minute means 60 s

And 39 s.

Total time in seconds = (7200+60+39)s

= 7299s

Now, converting the time in hours, we divide it by 3600.

So, $\frac{7299}{3600} = 2.0275 hours$

Now, we know that,

Speed (S) = Distance(D) / Time(T)

$= \frac{42.95 km}{2.0275h} \\= 20.811 km/h$

So, the speed in km/h is 20.811 km/hr.