SAT Question 699af7b3: Percentages answer and explanation with Desmos solution

It’s given that the weight of sample A is $468\%$ of the weight of sample B and $0.780\%$ of the weight of sample C. Let the weight of sample B be $b$ and the weight of sample C be $c$. Then, the weight of sample A is equivalent to $\frac{468b}{100}$, or $4.68b$, and also equivalent to $\frac{0.780c}{100}$, or $0.00780c$. Setting these expressions equal to each other yields $4.68b=0.00780c$. Dividing both sides of this equation by $0.00780$ yields $\frac{4.68b}{0.00780}=c$, or $c=600b$. If the weight of sample C is $p\%$ of the weight of sample B, then $c=\frac{p}{100}b$. Since $c=600b$ and $c=\frac{p}{100}b$, it follows that $600b=\frac{p}{100}b$, or $600=\frac{p}{100}$. Multiplying both sides of this equation by $100$ yields $60,000=p$. Therefore, the value of $p$ is $60,000$.