Question 1117666
Let {{{ n }}} = number of nickels
Let {{{ d }}} = number of dimes
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(1) {{{ n + d = 100 }}}
(2) {{{ 5n + 10d = 800 }}} ( in cents )
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Multiply both sides of (1) by {{{ 5 }}}
and subtract (1) from (2)
(2) {{{ 5n + 10d = 800 }}}
(1) {{{ -5n - 5d = -500 }}}
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{{{ 5d = 300 }}}
{{{ d = 60 }}}
and
(1) {{{ n + 60 = 100 }}}
(1) {{{ n = 40 }}}
There are 40 nickels and 60 dimes
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check:
(2) {{{ 5*40 + 10*60 = 800 }}}
(2) {{{ 200 + 600 = 800 }}}
(2) {{{ 800 = 800 }}}
OK