<PRE><B>Question 756380</B>
2680 ml. of the 81.8% alcohol.


Using v=volume of the pure alcohol, 100%, the add,

{{{highlight((2680*81.8+v*100)/(2680+v)=94.8)}}}
Solve for v.


{{{2680*81.8+v*100=94.8*2680+94.8*v}}}
{{{(100-94.8)v=(94.8-81.8)*2680}}}
just continue until done.</PRE>