Answer :
[tex]x- \cantity \ of \ substance \ contained \ by \ the \ tank \\ \\ \frac{4x}{5}+75= \frac{5x}{5} => \frac{x}{5}=75 \\ \\ \boxed{x=5*75=375 \ litres}[/tex]
full tank = 1 = 5/5
5/5 - 4/5 = 1/5
1/5 = 75
5/5 = 75 x 5 = 375
hope this helps(:
5/5 - 4/5 = 1/5
1/5 = 75
5/5 = 75 x 5 = 375
hope this helps(:
