Question 581242
Let x=amount of liquid fertilizer that needs to be added
Now we know that the amount of pure fertilizer that exists before the mixture takes place has to equal the amount of pure fertilizer that exists after the mixture takes place, sooooo:
x=0.25(600+x)
x=150+0.25x  subtract 0.25x from each side
x-0.25x=150
0.75x=150
x=200 ml----amount of liquid fertilizer needed
CK
200ml=0.25*800ml
200ml=200ml

Hope this helps---ptaylor