SAT Question 9a216c0f: Systems of Linear Equations answer and explanation with Desmos solution

Choice C is correct. It's given that $m$ represents the original price, in dollars, of the mirror, and $v$ represents the original price, in dollars, of the vase. It's also given that the combined original price for the mirror and the vase is $$60$. This can be represented by the equation $m+v=60$. After a $25\%$ discount to the mirror is applied, the sale price of the mirror is $75\%$ of its original price. This can be represented by the expression $0.75m$. After a $45\%$ discount to the vase is applied, the sale price of the vase is $55\%$ of its original price. This can be represented by the expression $0.55v$. It's given that the combined sale price for the two items is $$39$. This can be represented by the equation $0.75m+0.55v=39$. Therefore, the system of equations consisting of the equations $m+v=60$ and $0.75m+0.55v=39$ gives the original price $m$, in dollars, of the mirror and the original price $v$, in dollars, of the vase.