>>> from percentatge import preu_real

>>> round(preu_real(100, 16), 1)
116.0
>>> round(preu_real(150, 21), 1)
181.5
>>> round(preu_real(150, 10), 1)
165.0
>>> round(preu_real(78, 2), 1)
79.6
>>> round(preu_real(78, 4), 1)
81.1
>>> round(preu_real(78, 21), 1)
94.4