Respostas

2014-02-25T11:16:35-03:00
Achando a taxa mensal:

M=cx(1+i)
108000+3900=108000(1+i)
111900=108000+108000i
111900-108000=108000i
i=3900/108000
i=0,036 -- 3,6 % a.m x12 = 43,2 % a.a