SAT Question 38bf4e04: Linear Equations In One Variable answer and explanation with Desmos solution

Choice D is correct. It's given that during a certain day at a factory, the number of $7$ -inch concrete screws the factory makes is $n$ and the number of $4$ -inch concrete screws the factory makes is $22$. It's also given that during this day the number of $9$ -inch concrete screws the factory makes is $5$ times the number of $7$ -inch concrete screws, or $5n$. Therefore, the total number of $7$ -inch, $9$ -inch, and $4$ -inch concrete screws is $n+5n+22$, or $6n+22$. It's given that during this day, the factory makes $100$ concrete screws total. Thus, the equation $6n+22=100$ represents this situation.