Question 397607
Let N be the number of nickels, D the number of dimes.
1.{{{N+D=5}}}
.
.
{{{5N+10D=40}}}
2.{{{N+2D=8}}}
Subtract eq. 1 from eq. 2,
{{{N+2D-N-D=8-5}}}
{{{D=3}}}
Then from eq. 1,
{{{N+3=5}}}
{{{N=2}}}