I was following this guide. https://www.meebey.net/posts/ethereum_gpu_mining_on_linux_howto/

Basically its instructions are like this

sudo apt-get install software-properties-common

sudo add-apt-repository ppa:ethereum/ethereum

sudo apt-get update

sudo apt-get install ethereum ethminer

geth account new

# copy long character sequence within {}, that is your <YOUR_WALLET_ADDRESS>

# if you lose the passphrase, you lose your coins!

sudo apt-get install linux-headers-amd64 build-essential

chmod +x NVIDIA-Linux-x86_64-367.35.run

sudo NVIDIA-Linux-x86_64-367.35.run

ethminer -G -F http://yolo.ethclassic.faith:9999/0x<YOUR_WALLET_ADDRESS> --farm-recheck 200

On the command sudo apt-get install ethereum ethminer it fails with the error:

Reading package lists... Done

Building dependency tree       

Reading state information... Done

E: Unable to locate package ethminer

I did follow the instruction of adding the ethereum ppa so I am not sure why it will cannot find the ethminer package. Is the guide just out of date?