Question 462494
Let {{{ n }}} = number of nickels
Let {{{ d }}} = number of dimes
given:
(1) {{{ 5n + 10d = 315 }}} (in cents)
(2) {{{ n = 5d }}}
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Substitute (2) into (1)
(1) {{{ 5*(5d) + 10d = 315 }}}
(1) {{{ 25d + 10d = 315 }}}
(1) {{{ 35d = 315 }}}
(1) {{{ d = 9 }}}
and
(2) {{{ n = 5d }}}
(2) {{{ n = 45 }}}
Jeff has 9 dimes
check:
(1) {{{ 5n + 10d = 315 }}}
(1) {{{ 5*45 + 10*9 = 315 }}}
(1) {{{ 225 + 90 = 315 }}}
(1) {{{ 315 = 315 }}}
OK