Ubuntu 16.04: How to resolve libqt5x11extras5 (>= 5.1.0) but it is not going to be installed

Issue:

When you install Virtualbox 5.1 on Ubuntu 16.04, you may encounter following error:

root@XIAYE-NA1:~/Downloads# apt install virtualbox-5.1
Reading package lists... Done
Building dependency tree
Reading state information... Done
virtualbox-5.1 is already the newest version (5.1.14-112924~Ubuntu~xenial).
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
 libmagickcore-6.q16-2 : Depends: imagemagick-common (= 8:6.8.9.9-7ubuntu5.1) but 8:6.8.9.9-7ubuntu5 is to be installed
 libmagickwand-6.q16-2 : Depends: imagemagick-common (= 8:6.8.9.9-7ubuntu5.1) but 8:6.8.9.9-7ubuntu5 is to be installed
 virtualbox-5.1 : Depends: libqt5x11extras5 (>= 5.1.0) but it is not going to be installed
                  Depends: libsdl1.2debian (>= 1.2.11) but it is not going to be installed
                  Recommends: libsdl-ttf2.0-0 but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution)

Solution:

wget http://mirrors.kernel.org/ubuntu/pool/universe/q/qtx11extras-opensource-src/libqt5x11extras5_5.5.1-3build1_amd64.deb
dpkg -i libqt5x11extras5_5.5.1-3build1_amd64.deb
wget http://mirrors.kernel.org/ubuntu/pool/main/libs/libsdl1.2/libsdl1.2debian_1.2.15+dfsg1-3_amd64.deb
dpkg -i libsdl1.2debian_1.2.15+dfsg1-3_amd64.deb
dpkg -i virtualbox-5.1_5.1.14-112924~Ubuntu~xenial_amd64.deb