title: Error in installing gtools
body: <p>I am fairly new to R. I have tried to google my question, and tried a few things, to no avail.</p>
  
  <p>I am working on a <code>MAC</code> * <code>High Sierra version 10.13.5</code>
  I am working with <code>R</code> * <code>R version 3.5.0 (2018-04-23)</code> -- "Joy in Playing"</p>
  
  <p>I am unable to install the package "<code>gtools</code>", and I don't know what to do to make it work??</p>
  
  <p><code>install.packages("gtools", type="source")</code></p>
  
  <pre><code>Warning: unable to access index for repository https://mirrors.sorengard.com/cran/src/contrib:
    cannot open URL 'https://mirrors.sorengard.com/cran/src/contrib/PACKAGES'
  Warning message:
  package ‘gtools’ is not available (for R version 3.5.0) 
  </code></pre>
  
  <p>I have also tried to install from a file saved on my computer, but this did not work either</p>
  
  <pre><code>library(gtools)
  Error: package or namespace load failed for ‘gtools’:
   package ‘gtools’ was installed by an R version with different internals; it needs to be reinstalled for use with this R version
  </code></pre>