In reply to mmmhumous:
Was it 20m from one end? Your rope is probably xm longer than 40m, and your mark is probably 20m from one end and (20+x)m from the other, rather than (20 + x/2)m from each end
e.g. I once bought a 70m rope, measured it to be 72m, cut 30m off it as I wanted a 40m rope and my mate wanted a 30m and this was on a good deal...now...where do you expect the old middle mark to be on my 42m length?
If it had been a true 70m rope cut into a 30 and a 40, you would expect it to be 5m from one end of my 42. But I have a 42m rope, remember....
So do you think my middle mark is 7m from one end and 35m from the other (which means that originally it was 37m from one end and 35m from the other)?
If so, well done and have a biscuit.
Post edited at 17:42