quantity: 0 - 20 pairs, 21 - 40 pairs, 41 - 60 pairs, 61 - 80 pairs, 81 or more pairs. wholesale price (per…

Explanation:

Step1: Let $x$ be the quantity of pairs.

Let $y$ be the wholesale - price per pair.

Step2: For $0\leq x\leq20$, $y = 25$.

This is a constant - value function for this range.

Step3: For $21\leq x\leq40$, $y = 23$.

Another constant - value function for this range.

Step4: For $41\leq x\leq60$, $y = 21$.

Constant - value function for this range.

Step5: For $61\leq x\leq80$, $y = 19$.

Constant - value function for this range.

Step6: For $x\geq81$, $y = 17$.

Constant - value function for this range. We can write the piece - wise function: [y=\begin{cases}25, & 0\leq x\leq20\23, & 21\leq x\leq40\21, & 41\leq x\leq60\19, & 61\leq x\leq80\17, & x\geq81\end{cases}] The equation will work consistently for each range because the wholesale price is fixed within each given quantity range.

Answer:

[y=\begin{cases}25, & 0\leq x\leq20\23, & 21\leq x\leq40\21, & 41\leq x\leq60\19, & 61\leq x\leq80\17, & x\geq81\end{cases}]