Question 710390
Let {{{ d }}} = number of dimes that Lou has
Let {{{ q }}} = number of quarters that Julia has
given:
(1) {{{ d = q }}}
(2) {{{ 25q = 10d + 180 }}} ( in cents )
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Substitute (1) into (2)
(2) {{{ 25q = 10q + 180 }}}
(2) {{{ 15q = 180 }}}
(2) {{{ q = 12 }}}
and, since
(1) {{{ d = q }}}
(1) {{{ d = 12 }}}
Each has 12 coins
check:
(2) {{{ 25*12 = 10*12 + 180 }}} 
(2) {{{ 300 = 120 + 180 }}}
(2) {{{ 300 = 300 }}}
OK