title: installing R in ubuntu 20.04
body: <p>I am trying to re-install R in ubuntu 20.04
  when I use</p>
  <pre><code> sudo apt-get update 
  </code></pre>
  <p>I get the following error</p>
  <pre><code>Hit:1 http://dl.google.com/linux/chrome/deb stable InRelease
  Hit:2 https://cloud.r-project.org/bin/linux/ubuntu bionic-cran35/ InRelease    
  Hit:3 https://cloud.r-project.org/bin/linux/ubuntu focal-cran40/ InRelease     
  Hit:4 https://cloud.r-project.org/bin/linux/ubuntu xenial-cran40/ InRelease
  Hit:5 https://cloud.r-project.org/bin/linux/ubuntu bionic-cran40/ InRelease
  Hit:6 https://cloud.r-project.org/bin/linux/ubuntu eoan-cran35/ InRelease
  Hit:7 https://deb.leap.se/client release InRelease
  Ign:8 https://cloud.r-project.org/bin/linux/ubuntu bionic-cran InRelease
  Ign:9 https://cloud.r-project.org/bin/linux/ubuntu focal-cran36/ InRelease
  Err:10 https://cloud.r-project.org/bin/linux/ubuntu bionic-cran Release
    404  Not Found [IP: 143.204.201.112 443]
  Err:11 https://cloud.r-project.org/bin/linux/ubuntu focal-cran36/ Release
    404  Not Found [IP: 143.204.201.112 443]
  Err:12 https://repo.windscribe.com/ubuntu bionic InRelease
    Temporary failure resolving 'repo.windscribe.com'
  Reading package lists... Done         
  E: The repository 'https://cloud.r-project.org/bin/linux/ubuntu bionic-cran Release' does not have a Release file.
  N: Updating from such a repository can't be done securely, and is therefore disabled by default.
  N: See apt-secure(8) manpage for repository creation and user configuration details.
  E: The repository 'https://cloud.r-project.org/bin/linux/ubuntu focal-cran36/ Release' does not have a Release file.
  N: Updating from such a repository can't be done securely, and is therefore disabled by default.
  N: See apt-secure(8) manpage for repository creation and user configuration details.
  </code></pre>
  <p>can anyone please help me out ?</p>