Let's assume that Kirby walks with a speed
for a time
, and that he runs with a speed
for a time
.
The total time available for Kirby to catch the train is:
and this must be equal to the sum of the two times t1 and t2:
The distance Kirby should cover is
and this should be equal to the sum of the distances covered by walking and by running:
So we have a system of 2 equations:
If we solve the system, we find:
So, Kirby needs to run at least for 8 minutes in order to catch the train.
1) about 29.32
2) about 235.62
3) about 410.5
4) about 74220.13
5) about 366.52
6) about 1268.2
7) about 320.44
8) about 19.27
7^2 = 7x • 3
49 - 21x
-21x + 49