I have just measured a piece of string I found and the answer is 2' 3.5"! However, time is difficult to measure on a build. The 1:48 Mk IX spitfire was bought on a Saturday and finally finished the following Friday. How long I actually spent on it, I simply have no idea. The French Armoured carrier took a week and two days. If I had not spent so much time at work, on here, cooking, sorting out horrible (only kidding) kids, maybe three to four days less.
An interesting question so long as the answer does not matter. A kit should take as long to build as it does, and no less. I have a couple of part built kits started in December bt I could not say it has taken three months to build them.
I try to have one main kit on the go but I can happily demote it if something else comes along. The Eurofighter Typhoon I have on the go has been demoted by the French carrier and although very nearly finished, it has been demoted to secondary finishing while starting a new project. This, in the case of the typhoon, is simply because I have found it becoming boring and I don't want to rush it to completion and spoil it simply because I am bored. I would rather keep doing a little bit every now and again until it is finished. As well as that I have three other kits on the go, my horse drawn stuff which I really need to get back to soon.