Actually I got this question in job interview and successfully failed it ( it was obvious eliminating question ). I recall the Ramsey theory and cited the famous result on existence of cliques with edges of same color. But they then asked me to discuss how to estimate the probability that in fully connected graph there is a clique where edge colors are all different? Namely, they said: "Imagine that in a fully-connected graph, each edge is painted with one of two colours. Estimate the probability that the graph contains a fully-connected subgraph on 3 vertices that has edges of different colours"
I read a lot of articles but it does not look as naive result, which anyone knows since college graduation. So any help/hints/links are highly appreciated.