Unable to install ruby 2.4.0 on mac

Hi i'm unable to install ruby 2.4.0

rvm version >> 1.29.1

rubygems version >> 2.6.11

I'm trying to install ruby 2.4.0 using the below command :

rvm install ruby-2.4.0

I'm getting the following error :

    Searching for binary rubies, this might take some time.
No binary rubies available for: osx/10.11/x86_64/ruby-2.4.0.
Continuing with compilation. Please read 'rvm help mount' to get more information on binary rubies.
Checking requirements for osx_brew.
Installing requirements for osx_brew.
Updating system...........
Error running 'requirements_osx_brew_update_system ruby-2.4.0',
showing last 15 lines of /Users/bbc-admin/.rvm/log/1492510247_ruby-2.4.0/update_system.log
    http://ift.tt/1nuoqLP
and make sure `brew update` works before continuing.'
++ rvm_pretty_print stderr
++ case "${rvm_pretty_print_flag:=auto}" in
++ case "${TERM:-dumb}" in
++ case "$1" in
++ [[ -t 2 ]]
++ return 1
++ printf %b 'Failed to update Homebrew, follow instructions here:
    http://ift.tt/1nuoqLP
and make sure `brew update` works before continuing.\n'
Failed to update Homebrew, follow instructions here:
    http://ift.tt/1nuoqLP
and make sure `brew update` works before continuing.
++ return 1
Requirements installation failed with status: 1.

Please help me.. thanks in advance.