Question 539159
{{{n}}} = number of nickels
{{{d}}} = number of dimes
given:
{{{ d = 2n }}}
{{{ 5n + 10d = 1050 }}} ( in cents )
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Use substitution
{{{ 5n + 10*(2n) = 1050 }}}
{{{ 25n = 1050 }}}
{{{ n = 42 }}}
and, since
{{{ d = 2n }}}
{{{ d = 84 }}}
She has 42 nickels and 84 dimes
check:
{{{ 5*42 + 10*84 = 1050 }}}
{{{ 210 + 840 = 1050 }}}
{{{ 1050 = 1050 }}}
OK