<PRE><B>Question 536472</B>
Let the nickels be x
Dimes = y

5x+10y=960---------------(1)

5(3x)+10(y-31)=670

15x+10y-310=670
15x+10y=980 ---------------(2)
Multiply equation (1) by -3
we get
-15x-30y=-2880
Add this equation to (2)
-20y=-1900
/-20
y=95 ---- dimes
plug x in any equation you get x=2 nickels
CHECK
5*2+10*95=960

</PRE>