title: Failed to fetch archives while installing gcc-4.9 g++-4.9
body: <p>Currently, I am using Linux Mint 17.3.</p>
  
  <p><code>E: Failed to fetch http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu/pool/main/g/gcc-4.9/cpp-4.9_4.9.3-8ubuntu2~14.04_amd64.deb  Hash Sum mismatch</code></p>
  
  <p><code>E: Failed to fetch http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu/pool/main/g/gcc-4.9/g++-4.9_4.9.3-8ubuntu2~14.04_amd64.deb  Hash Sum mismatch</code></p>
  
  <p><code>E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?</code></p>