failed to install R in Ubuntu 20.04 focal

i tried to install R on Ubuntu20.04 focal. but i got error "unmet dependencies".

Reading package lists... Done  Building dependency tree  Reading state information... Done  Some packages could not be installed. This may mean that you have  requested an impossible situation or if you are using the unstable  distribution that some required packages have not yet been created  or been moved out of Incoming.  The following information may help to resolve the situation:    The following packages have unmet dependencies:   r-base : Depends: r-base-core (>= 4.0.3-1.2004.0) but it is not going to be installed            Depends: r-recommended (= 4.0.3-1.2004.0) but it is not going to be installed            Recommends: r-base-html but it is not going to be installed            Recommends: r-doc-html but it is not going to be installed  E: Unable to correct problems, you have held broken packages.  

i did following things

apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9    add-apt-repository 'deb https://cloud.r-project.org/bin/linux/ubuntu focal-cran40/'  

but those did not work.

release info

DISTRIB_ID=Ubuntu  DISTRIB_RELEASE=20.04  DISTRIB_CODENAME=focal  DISTRIB_DESCRIPTION="Ubuntu 20.04.2 LTS"  enter code here  

please help me to install R.

https://stackoverflow.com/questions/65948176/failed-to-install-r-in-ubuntu-20-04-focal January 29, 2021 at 10:56AM