How long will a gas mower go on the same amount of energy as an electric mower.

Hi Fellow steemers.
Ever wonder just how effecnient gas is at powering tools compared to electric.
This Fully charged episode Is a bit old so the batteries are now a bit better.

https://m.youtube.com/watch?feature=youtu.be&v=AFPRvfNW-Qs

Ya I know not a picture of a mower but they will charge the battery.