Question 1120729
{{{system(0.25q+0.1d+0.05n=2.55,n=2d,n-q=1)}}}


Look at the last two equations carefully.
{{{system(d=n/2,q=n-1)}}}

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simplify the money sum equation.
{{{5q+2d+n=51}}}



Substitute for d and q.
{{{5(n-1)+2(n/2)+n=51}}}
Find value of n from this equation.
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{{{5n-5+n+n=51}}}

{{{7n=51+5}}}

{{{7n=56}}}

{{{highlight(n=8)}}}
and you can find the other two coin counts.