Question 128502
{{{d}}} = number of dimes
{{{n}}} = number of nickels
{{{n + d = 40}}}
{{{d = 40 - n}}}
{{{5n + 10d = 380}}}
{{{5n + 10(40 - n) = 380}}}
{{{5n + 400 - 10n = 380}}}
{{{-5n = -20}}}
{{{n = 4}}}
{{{d = 40 - n}}}
{{{d = 36}}}
He has 4 nickels and 36 dimes
check answer:
{{{5n + 10d = 380}}}
{{{5*4 + 10*36 = 380}}}
{{{20 + 360 = 380}}}
{{{380 = 380}}}
OK