Back in the Good Old Days (for me) of Knight Rider, Miami Vice, big hair and pastel clothing i.e. the early-mid 80s, as a young soldier we were taught the 3-1 ratio as applicable against a like opponent i.e. the classic Commonwealth section with 1 MG, and 7-9 riflemen (with semi-automatic rifles) ...so a rifle platoon should be able to successfully engage a rifle section, a company a platoon, etc etc...the reference material for this would have been one or some of the pubs in fine Aussie series The Manual of Land Warfare (MLW)...however...if the adversary was armed along the Soviet model where every soldier had an automatic weapon like an AK, the ratio was 10-1 especially if the adversary was in a defended position...

Going up to 10-1 may have been a simplification for young soldiers by simply increasing the level of engagement from platoon to company as I do recall that some instructors referred to this increase as a Soviet lesson so the 6-1 above may be quite correct...

Our network is down at the moment but I have most of these pubs in the library and will do some research once it is back up...