Unable to install php7.1 on ubuntu trusty 64 in vagrant

I have just tried many of the solution to install php7.1 on my ubuntu trusty 64 running in vagrant machine.

I have followed the following commands:

sudo apt-get install python-software-properties -y 

and then

sudo add-apt-repository ppa:ondrej/php  sudo apt-get update 

but when I run:

sudo apt-get install php7.1 

I get the following error:

E: Unable to locate package php7.1

E: Couldn’t find any package by regex ‘php7.1’

Can anyone please help me to install php7.1 on Ubuntu 14.01 in Vagrant ?