Question 615968
Let {{{n}}} = number of nickels
Let {{{d}}} = number of dimes
(1) {{{ 5n + 10d = 200 }}} ( in cents )
(2) {{{ d = 2n }}}
Substitute (2) into (1)
(1) {{{ 5n + 10*2n = 200 }}}
(1) {{{ 25n = 200 }}}
(1) {{{ n = 8 }}}
and, since
(2) {{{ d = 2n }}}
(2) {{{ d = 16 }}}
She has 8 nickels and 16 dimes
check:
(1) {{{ 5n + 10d = 200 }}}
(1) {{{ 5*8 + 10*16 = 200 }}}
(1) {{{ 40 + 160 = 200 }}}
(1) {{{ 200 = 200 }}}
OK