Question 273095
Let {{{n}}} = number of nickels
Let {{{d}}} = number of dimes
given:
{{{n + d = 11}}}
{{{d = n + 3}}}
{{{5n + 10d = 90}}}
By substitution:
{{{5n + 10*(n + 3) = 90}}}
{{{5n + 10n + 30 = 90}}}
{{{15n = 90 - 30}}}
{{{15n = 60}}}
{{{n = 4}}}
and
{{{n + d = 11}}}
{{{4 + d = 11}}}
{{{d = 7}}}
She has 7 dimes and 4 nickels
check:
{{{5n + 10d = 90}}}
{{{5*4 + 10*7 = 90}}}
{{{20 + 70 = 90}}}
{{{90 = 90}}}
OK