I don’t know why the command \input don’t work in the package answers. If I use \include it’s OK but it’s not good because some things don’t work correctly. Only under TexPad editor.
It seems that in texpad everything that is written during the compilation is placed in the .texpadtmp directory. Here you can find your temporary answer file. But then things get messed up if you use the include command, because the file cannot be found in the root directory.
To fix this, just write