Question 937905

You have $3.70 in dimes and quarters. You have 5 more quarters than dimes. How many of each coin do you have

let dimes be {{{d}}}  and quarters {{{q}}}

if you have {{{5}}} more quarters than dimes, then {{{q=d+5}}}

if you have ${{{3.70} }}, then you have 

{{{3.70=0.25*q+0.10d} }} ...substitute  {{{d+5}}} for  {{{q}}}

{{{3.70=0.25*(d+5)+0.10d} }}

{{{3.70=0.25d+0.25*5+0.10d}}}

{{{3.70=0.35d+1.25}}}
{{{3.70-1.25=0.35d}}}

{{{2.45=0.35d}}}

{{{2.45/0.35=d}}}

{{{highlight(d=7)}}}

 {{{q=d+5}}}

 {{{q=7+5}}}=> ${{{0.10*7=0.70}}}

 {{{highlight(q=12)}}}  =>${{{0.25*12=3}}}   => together ${{{3.70}}}