Question

Que taxa mensal faz um capital de 600 reais render 75 reais em 5 meses?

Answer 1

Juros simples

$J=Cit\Rightarrow i= \dfrac{J}{Ct}= \dfrac{75}{600\cdot5}= \dfrac{75}{3.000}=0,025\times100=2,5\%$

Juros compostos

$M=J+C\Rightarrow M=675\\\\ M=C(1+i)^t\\ 675=600\cdot(1+i)^5\\\\ (1+i)^5= \dfrac{675}{600}\\\\ (1+i)^5=1,125\\ 1+i= \sqrt[5]{1,125} \\ 1+i\approx1,0238\\ i\approx1,0238-1\\ i\approx0,0238~~\times~~100\\\\ i\approx2,38\%$