Question 998782
The description is poor.  What sizes are those two "bottles"?  Given is  ONE bottle of pure antifreeze and ONE bottle of 10% antifreeze; making available only TWO bottles.  


On the other hand, the question asks for 8 liters of 77.5% antifreeze.  Maybe each bottle is big enough to carry about 4 liters each?  The question asks for how many liters, and not how many bottles.


v, how many liters of the pure antifreeze
8-v, how many... 10%


{{{highlight_green((100*v+(8-v)10)/8=77.5)}}}


{{{100v+80-10v=8*77.5}}}

{{{90v+80=8*77.5}}}

{{{90v=8*77.5-80}}}

{{{highlight(v=6)}}}------Six liters of the pure antifreeze
therefore  2 liters of the 10% antifreeze.



Now again, HOW BIG IS EACH BOTTLE?