As one would expect?

 2:51 >perl -e "printf qq[%s => %.20f => %.1f\n], (qq[0.${_}5]) x 3 fo
+r (0..9)"
0.05 => 0.05000000000000000300 => 0.1
0.15 => 0.14999999999999999000 => 0.1
0.25 => 0.25000000000000000000 => 0.3
0.35 => 0.34999999999999998000 => 0.3
0.45 => 0.45000000000000001000 => 0.5
0.55 => 0.55000000000000004000 => 0.6
0.65 => 0.65000000000000002000 => 0.7
0.75 => 0.75000000000000000000 => 0.8
0.85 => 0.84999999999999998000 => 0.8
0.95 => 0.94999999999999996000 => 0.9
[download]

:-)