discount comics is running a special: 20 comi...

# Answer: 1. $0.25$ 2. $0.25$ # Explanation: ## Step1: Calculate sale - price per comic We know that for the special offer, 20 comics cost $5.00$. The sale - price per comic is calculated by dividing the total cost by the number of comics. Let $p$ be the price per comic. Using the formula $p=\frac{C}{n}$, where $C$ is the total cost and $n$ is the number of comics. For the first case, $C = 5$ and $n = 20$, so $p=\frac{5}{20}=0.25$. We can also check with Seth's purchase: when $C = 7.50$ and $n = 30$, $p=\frac{7.50}{30}=0.25$. ## Step2: Determine the constant of proportionality In a proportional relationship $y = kx$, where $y$ is the total cost, $x$ is the number of comics, and $k$ is the constant of proportionality. The constant of proportionality is the price per comic. Since the price per comic is $0.25$, the constant of proportionality $k = 0.25$.