SAT Question fe4c1c9e: Ratios Rates Proportional Relationships And Units answer and explanation with Desmos solution

It's given that a mechanical device produces items at a constant rate of $60$ items per hour. This rate can be written as $\frac{60\text{items}}{1\text{hour}}$. Let $x$ represent the number of items the mechanical device will produce in $3$ hours at the given rate. It follows that $\frac{60\text{items}}{1\text{hour}}=\frac{x\text{items}}{3\text{hours}}$, which can be written as $\frac{60}{1}=\frac{x}{3}$, or $60=\frac{x}{3}$. Multiplying each side of this equation by $3$ yields $180=x$. Therefore, at the given rate, the mechanical device will produce $180$ items in $3$ hours.

Alternate approach: It's given that a mechanical device produces items at a constant rate of $60$ items per hour. At this rate, the mechanical device will produce $\left(\frac{60\text{items}}{1\text{hour}}\right)\left(3\text{hours}\right)$, or $180$ items in $3$ hours.