Question

na compra de aparelho obtive desconto de 15% por ter feito o pagamento à vista se eu pagar 102reais pelo aparelho , qual era o teu preço original? ...

Answer 1

85℅----102
100%----x
85x=10200
x=10200/85
x=120

Answer 2

$\sf \bullet \underbrace{\sf Veja \to}\\\\\\\tt 85x=102\cdot100\\\\\\\tt 85x=10200\\\\\\\tt\dfrac{85x}{85}= \dfrac{10200}{85}\\\\\\\to \boxed{\tt x=120R\ \ PRE\c{C}O\ NORMAL}$