worth 2.20=worth of nickles+worth of dimes worth of nickles=number of nickes times 0.05=0.05n worth of dimes=number of dimes times 0.10 so 2.2=0.05n+0.1d
so we have n+d=36 2.2=0.05n+0.1d
multiply the second equaiton by -10 -22=-0.5n-1d add to first equation 36+n+d -22=-0.5n-d + 14=0.5n+0d
