Problem Solving

Hello Vjesus12.

Let's take a look at your question.

We have to solve this two-equation system: $$x=y+3+4.5x\ \ \ --\ --\left(1\right)$$ $$y=x+18\ \ \ --\ --\left(2\right)$$ If we replace the second equation into the first one we get $$x=\left(x+18\right)+3+4.5x\ \ \ \Rightarrow\ \ \ \ x=21+5.5x$$ $$-21=5.5x-x\ \ \ \Rightarrow\ \ \ \ -21=4.5x\ \ \ \Rightarrow\ \ \ x=-\frac{21}{4.5}.$$ Now, we can find the value of y as follows: $$y=x+18\ \ \Rightarrow\ \ \ y=-\frac{21}{4.5}+18\ =\ \frac{60}{4.5}.$$ Finally, we can get the value of x/y $$\frac{x}{y}=\frac{-\frac{21}{4.5}}{\frac{60}{4.5}}=-\frac{21}{60}=-\frac{7}{20}.$$ This implies that the correct answer is the option B.

I hope it is clear enough.

Regards.