When you say 'top nock', do you mean the top tip of the bow?
You can figure out how many strands you have by untwisting the string. You'll see 'major' strands and 'minor' ones. Multiples of the minor ones make the majors. You should be able to see what we mean.
55@31 translates into something like 46@28.
Was your string 'flemish' or 'continuous'?