Question 235870
let {{{d}}} = number of dimes
Let {{{q}}} = number of quarters
given:
(1) {{{d + q = 20}}}
(2) {{{10d + 25q = 275}}} (in cents)
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Multiply both sides of (1) by {{{10}}} and
subtract from (2)
(2) {{{10d + 25q = 275}}}
(1) {{{-10d - 10q = 200}}}
{{{15q = 75}}}
{{{q = 5}}}
and, since
{{{d + q = 20}}}
{{{d + 5 = 20}}}
{{{d = 15}}}
There are 5 quarters and 15 dimes