Question 1163703
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 mix a solution that is 4% Minoxidil. She has on hand 90 ml of a 2% solution and wishes to add some 6% solution to obtain the desired 4% solution. How much 6% solution should she add?
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{{{90*0.02+v*(0.06)=(90+v)*(0.04)}}}

{{{highlight_green(0.06v+0.02*90=0.04(v+90))}}}

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{{{0.06v+0.02*90=0.04v+0.04*90}}}

{{{(0.06-0.04)v=0.04*90-0.02*90}}}

{{{(0.06-0.04)v=90(0.04-0.02)}}}

{{{highlight(v=90((0.04-0.02)/(0.06-0.04)))}}}-------compute this.