SAT Question 0d1b1e35: Linear Equations In Two Variables answer and explanation with Desmos solution

Choice A is correct. It’s given that a batch of banana milkshakes consists of $4$ cups of ice cream and $2$ bananas and has $1,114$ mg of calcium. It’s also given that there is $276$ mg of calcium in $1$ cup of the ice cream used to make this batch of milkshakes. It follows that the total amount of calcium in $4$ cups of ice cream is $4(276)$, or $1,104$ mg. Let $x$ represent the amount of calcium, in mg, in $1$ banana. It follows that the total amount of calcium in $2$ bananas is $2x$ mg. Since the batch of banana milkshakes has $1,114$ mg of calcium, the equation $1,104+2x=1,114$ represents this situation. Subtracting $1,104$ from both sides of this equation yields $2x=10$. Dividing both sides of this equation by $2$ yields $x=5$. Therefore, the amount of calcium in $1$ banana is $5$ mg.