Assuming x = nickels,
y = quarters
[tex]x + y = 10 \\ 0.05x + 0.25y = 1.05[/tex]
[tex]x = 10 - y[/tex]
Substitute that into
[tex]0.05(10 - y) + 0.25y = 1.05 \\ 0.5 - 0.05y + 0.25y = 1.05 \\ 0.2y = 0.55 \\ y = 2.75[/tex]
[tex]x + 2.75 = 10 \\ x = 7.25[/tex]
Hope this helps. - M