I've been working on it, but still haven't found the answer. The only way I could think of setting it up was like this:
1.575 + .63e + .47f = 37.9
With 1.575 being added for England's additional 2.5 months, the e being England and the f being France. But that would not work out without more information being given out. It just sounds like it won't work unless I know how many months the thing took to build or how much one of the countries contributed.
I only have one hour to solve five of these word problems, so any help would seriously be appreciated.