Question

Calcule x e y na proporção x/y= 4/2, sabendo que x + y = 12.

a) 0 e 4

b) 8 e 4

c) 8 e 0

d) 4 e 4

e) 8 e 8.

Answer 1

$\large\boxed{\begin{array}{l}\rm\dfrac{x}{y}=\dfrac{4}{2}\\\\\rm\dfrac{x}{y}=2\longrightarrow x=2y\\\rm x+y=12\\\\\rm 2y+y=12\\\rm 3y=12\\\rm y=\dfrac{12}{3}\\\\\rm y=4\\\rm x=2y\\\rm x=2\cdot4\\\rm x=8\\\huge\boxed{\boxed{\boxed{\boxed{\rm\dagger\red{\maltese}~\blue{alternativa~b}}}}}\end{array}}$