Question 259649
1.{{{N+D=500}}}
2.{{{5N+10D=3000}}}
From eq. 1,
{{{N=500-D}}}
Substitute into eq. 2 and solve for D.
2.{{{5N+10D=3000}}}
{{{5(500-D)+10D=3000}}}
{{{2500-5D+10D=3000}}}
{{{5D=500}}}
{{{D=100}}}
Now use eq. 1,
{{{N=500-D}}}
{{{N=500-100}}}
{{{N=400}}}
There are 400 nickels and 100 dimes.