A can of juice was $80\%$ full. $80\%$ of the contents were emptied into a glass and $81$ ml of juice was added to the can. Then the can became full to the brim. What is the capacity of the can ?
If $x$ ml be the full capacity of the can then $\frac 4{25}x + 81 = x$ but then solving for $x$ from here won't give $225$ ml which is the required answer for this problem. What exactly I am missing here?