Question

eu tinha R$ 50 reais no bolso gastei 50% desse dinheiro comprando jogo, e depois gastei 20% do que sobrou com doces. Quanto eu gastei no total?

Answer 1

$\mathtt{Usaremos~regra~de~3: 100\% - 50\% = 50\%} \\ \\\mathtt{R\ ~~~~~~\%} \\ \mathtt{50~~~~~100} \\ \mathtt{x~~~~~~~50} \\ \\ \mathtt{100x = 50 \times 50} \\ \mathtt{100x = 2.500} \\ \mathtt{x = 2.500 \div 100} \\ \mathtt{x =25} \\ \\ \mathtt{Regra~de~3: 100\% - 20\% = 80\%} \\ \\ \mathtt{R\ ~~~~~~~~\%} \\ \mathtt{25~~~~~~~100} ~\\\mathtt{x~~~~~~~~~80} \\ \\ \mathtt{100x = 80 \times 25} \\ \mathtt{100x =2.000 } \\ \mathtt{x = 2.000 \div 100} \\ \mathtt{x =20 } \\ \\ \mathtt{R\ ~50,00 - R\%~20,00=30,00}$

$\boxed{\boxed{\mathtt{ Resposta: Gastou~no~total ~~~ R\ ~30,00}}}$