SAT Question 52a8ef85: Linear Equations In Two Variables answer and explanation with Desmos solution

Choice B is correct. It's given that the equation $40x+20y=160$ represents the number of sweaters, $x$, and the number of shirts, $y$, that Yesenia purchased for $$160$. If Yesenia purchased $2$ sweaters, the number of shirts she purchased can be calculated by substituting $2$ for $x$ in the given equation, which yields $40\left(2\right)+20y=160$, or $80+20y=160$. Subtracting $80$ from both sides of this equation yields $20y=80$. Dividing both sides of this equation by $20$ yields $y=4$. Therefore, if Yesenia purchased $2$ sweaters, she purchased $4$ shirts.