Question

Como se resolve?
Qual deve ser o capital aplicado a uma taxa de juro simples de 25% a.a. para que em 6 meses renda R$ 425,00 de juro?

Answer 1

0,5ano = R$425,00
R$425,00(2) = 25%
R$850,00 = 25%

850 ---- 25%
x --------100%
25x=100(850)
25x=85000
x=85000 / 25
x=3400

O capital é R$3.400.

Espero ter ajudado!

Answer 2

$\sf\large \boxed{\boxed{\tt J = C \cdot i \cdot t}}$

_______________________

$\sf \displaystyle 425\:=\:C\:\cdot 0,\:25\:\cdot \left(\frac{1}{2}\right)\\\\\\\sf \boxed{\star \sf \ {Troque \:os \:lados} }\\\\\\\sf C\cdot \:0.25\left(\frac{1}{2}\right)=425\\\\\\\sf C\frac{0.25}{2}=425\\\\\\\sf 2C\frac{0.25}{2}=425\cdot \:2\\\\\\\sf 0.25C=850\\\\\\\sf \frac{0.25C}{0.25}=\frac{850}{0.25}\\\\\\\\\large \to \boxeed{\boxed{\sf C=3400}}$