sudo aptitude install paratext-7.5
The following NEW packages will be installed:
  paratext-7.5 paratext-mono{ab}
0 packages upgraded, 2 newly installed, 0 to remove and 0 not upgraded.
Need to get 82.9 MB of archives. After unpacking 281 MB will be used.
The following packages have unmet dependencies:
 paratext-mono : Depends: mono-runtime (<= 3.2.9) but 4.6.2.16-0xamarin1 is installed. or
                          mono-runtime (<= 4.2.2) but 4.6.2.16-0xamarin1 is installed.
                 Depends: libmono-corlib4.0-cil (<= 3.2.9) but it is not going to be installed. or
                          libmono-corlib4.5-cil (<= 4.2.2) but 4.6.2.16-0xamarin1 is installed.
The following actions will resolve these dependencies:

     Keep the following packages at their current version:
1)     paratext-7.5 [Not Installed]
2)     paratext-mono [Not Installed]



Accept this solution? [Y/n/q/?] y
No packages will be installed, upgraded, or removed.
0 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B of archives. After unpacking 0 B will be used.