Problem K. 774. (September 2023)

K. 774. A train is passing through a tunnel at a uniform speed. It takes 20 seconds, from the front of the train entering the tunnel to the rear end of the train emerging from the tunnel. A lamp hanging from the ceiling of the tunnel remains above the train for exactly 5 seconds. How long is the train?

(5 pont)

Deadline expired on October 10, 2023.

Sorry, the solution is available only in Hungarian. Google translation

Megoldás. 20 másodperc alatt az alagút hosszát plusz egy saját hossznyit tesz meg a vonat. 5 másodperc alatt pedig pont egy vonathossznyit (amíg elhalad a lámpa alatt). Ezek alapján 300 m = 3 vonatnyi hossz, azaz a vonat 100 m hosszú.

Statistics:

200 students sent a solution.
5 points:	75 students.
4 points:	11 students.
3 points:	6 students.
2 points:	5 students.
1 point:	7 students.
0 point:	2 students.
Not shown because of missing birth date or parental permission:	94 solutions.

Problems in Mathematics of KöMaL, September 2023