[Tutor] Is something wrong with my round() function?

[hcohen2]

The obvious answer is 'YES', but what's causing this strange behaviour?

 >>> ans = 48.936
 >>> round(ans, 1)
48.899999999999999
 >>> round(ans, 2)
48.939999999999998
 >>> round(ans, 3)
48.936
 >>> round(ans, 4)
48.936
 >>> round(ans, 2)
48.939999999999998
 >>> round(ans, 1)
48.899999999999999
 >

I have another example were I was using a class to compute the total 
room rates that were supposed to be rounded to the nearest cent and they 
looked like the above sample, however, using the round(<week rate>, 1) 
gave it properly to the nearest dime.

Using python ver 2.2.2 on Linux (Mandrake 9.1) on an IBM laptop.

TIA