Question: A gift shop sells stickers. The store sells 8 stickers for $3.
Which of the following statements are true when $y$ represents the cost for purchasing $x$ stickers?
Select all that apply.
The rate of change is $\frac{8}{3}$.
The slope of the equation is $\frac{8}{3}$.
The rate of change is $\frac{3}{8}$.
The slope of the equation is $\frac{3}{8}$.
The unit rate is $\frac{3}{8}$ dollars per sticker.
The constant of proportionality in this situation is $\frac{8}{3}$.
1. **State the problem:**
We know the store sells 8 stickers for 3 dollars. We want to analyze the statements about the rate of change, slope, unit rate, and constant of proportionality when $y$ is the cost for $x$ stickers.
2. **Identify the variables and relationship:**
- $x$ = number of stickers
- $y$ = cost in dollars
Since 8 stickers cost 3 dollars, the cost per sticker (unit rate) is:
$$\text{unit rate} = \frac{3}{8} \text{ dollars per sticker}$$
3. **Write the equation relating $y$ and $x$:**
The cost $y$ is proportional to the number of stickers $x$:
$$y = \frac{3}{8} x$$
Here, the slope (rate of change) is $\frac{3}{8}$.
4. **Analyze each statement:**
- "The rate of change is $\frac{8}{3}$": **False** because rate of change is cost per sticker, which is $\frac{3}{8}$.
- "The slope of the equation is $\frac{8}{3}$": **False** for the same reason.
- "The rate of change is $\frac{3}{8}$": **True** because cost increases by $\frac{3}{8}$ dollars per sticker.
- "The slope of the equation is $\frac{3}{8}$": **True** because slope equals rate of change in this linear equation.
- "The unit rate is $\frac{3}{8}$ dollars per sticker": **True** by definition.
- "The constant of proportionality in this situation is $\frac{8}{3}$": **False** because the constant of proportionality is the multiplier from $x$ to $y$, which is $\frac{3}{8}$.
5. **Final answers:**
The true statements are:
- The rate of change is $\frac{3}{8}$.
- The slope of the equation is $\frac{3}{8}$.
- The unit rate is $\frac{3}{8}$ dollars per sticker.