Then we have four equal possibilities. The segment BOC can be either on top or underneath at each of the points B and C.

Segment BOCHence the chance that the rope is knotted is 1/4.At BAt CThe rope isOn top On top Not knotted On Top Under Not knotted Under On top Knotted Under Under Not knotted

Source: Longley-Cook, L. H.

Categories: Reasoning, Probability, Topology

[Top | Problem]