Problem P. 4295. (December 2010)
P. 4295. When a ruler is supported from below, 15 cm from one of its ends, then the ruler can be balanced with two alike coins, placed 5 cm from the end of the ruler. When the support is placed 1 cm from the same end of the ruler it can be balanced with six alike coins, at the same position. How long is the ruler?
Deadline expired on January 10, 2011.
Sorry, the solution is available only in Hungarian. Google translation
Megoldás. A forgatónyomatékok egyensúlyát felírva a két esetben a vonalzó hosszára 50 cm adódik.
214 students sent a solution. 3 points: 135 students. 2 points: 33 students. 1 point: 28 students. 0 point: 10 students. Unfair, not evaluated: 8 solutions.