Rounding Off A No. With Limitation

Here it is:

I used ceiling and floor for this but it was futile.

I was hoping to round off a no. according to the limitations set,

For example:
Sample Entries Preferred Rounded-off nos.
Cell A1 Cell B1
.40 .40
.39 .40
.38 .40
.37 .35
.36 .35
.35 .35
.34 .35
.33 .35
.32 .30
.31 .30
.30 .30

When using ceiling and floor formulas there was an error prompt telling me that there are too many arguments.