Question 901130
c = how many color copies
b = how many Black and white copies


{{{system(0.10b+0.75c=16,b+c=56)}}}


{{{system(10b+75c=1600,b+c=56)}}}


Divide members of cost equation by 5,
{{{system(2b+15c=320,b+c=56)}}}


Use two times the copies account equation,
{{{system(2b+15c=320,2b+2c=112)}}}


Subtract equations,
{{{13c=320-112}}}
{{{13c=208}}}
{{{highlight(c=16)}}}
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{{{highlight(b=40)}}}