SAT Question 8368afd1: Linear Equations In Two Variables answer and explanation with Desmos solution

Choice B is correct. It's given that the graph shows the possible combinations of the number of pounds of tangerines, $x$, and the number of pounds of lemons, $y$, that could be purchased for $$18$ at a certain store. If Melvin purchased lemons and $4$ pounds of tangerines for a total of $$18$, the number of pounds of lemons he purchased is represented by the y-coordinate of the point on the graph where $x=4$. For the graph shown, when $x=4$, $y=10$. Therefore, if Melvin purchased lemons and $4$ pounds of tangerines for a total of $$18$, then he purchased $10$ pounds of lemons.