Question 803293
Let w = grams of Silver to add, to dilute the gold.


{Amount of gold}/{Amount of alloy} = {81% or 0.81}


{{{(18*6*0.93)/(18*6+w)=0.81}}} to use decimal fractions instead of "percents".
{{{18*6*0.93=0.81(18*6+w)}}}
{{{0.81*18*6+0.81w=18*6*0.93}}}
{{{0.81w=18*6*0.93-0.81*18*6}}}
{{{0.81w=18*6(0.93-0.81)}}}
{{{0.81w=0.04(18*6)}}}
{{{w=(0.04*6*18)/0.81}}}
{{{w=4*6*18/81}}}
{{{w=(2*2*2*3*2*3*3)/(3*3*3*3)}}}
{{{w=(2*2*2*2*3*3*3)/(3*3*3*3)}}}
{{{highlight(w=16/3=5&1/3)}}} grams of Silver