"Check if you are using third party repositories. If so disable them, since they are a common source of problems.
Furthermore run the following command in a terminal:
apt-get install -f"
The following packages have unmet dependencies:
fgfs-models-base: flightgear: Depends: libc6 (>= 2.14) but 2.15-0ubuntu20 is installed Depends: libgcc1 (>= 1:4.1.1) but 1:4.7.2-2ubuntu1 is installed Depends: libstdc++6 (>= 4.6) but 4.7.2-2ubuntu1 is installed Depends: libudev0 (>= 147) but 175-0ubuntu13 is installed Depends: zlib1g (>= 1:1.1.4) but 1:1.2.7.dfsg-13 is installed