Question 857906
{{{d}}}= number of dimes used.
{{{0.1d}}}= amount paid, in $.
{{{d-18}}}= number of quarters needed to pay using only quarters.
{{{0.25(d-18)}}}= amount those quarters add up to, in $.
{{{0.25(d-18)=0.1d}}}
{{{0.25d-4.5=0.1d}}}
{{{0.25d-0.1d-4.5=0}}}
{{{0.15d-4.5=0}}}
{{{0.15d=4.5}}}
{{{d=4.5/0.15}}}
{{{d=30}}}
{{{0.1d=0.1*30=highlight(3)}}} is the amount paid, in $.