Question 800418
{{{ d = 2n }}}
{{{ 10d  = 5n + 165 }}}
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By substitution:
{{{ 10*( 2n ) = 5n + 165 }}}
{{{ 20n = 5n + 165 }}}
{{{ 15n = 165 }}}
{{{ n = 11 }}}
and
{{{ d = 2n }}}
{{{ d = 2*11 }}}
{{{ d = 22 }}}
There are 11 nickels and 22 dimes
check:
{{{ 11*5 = 55 }}}
{{{ 22*10 = 220 }}}
{{{ 220 - 55 = 165 }}}
OK