To solve the problem, we need to work through the steps you've outlined. The function you're given represents the weekly sales of an electronics store as a function of the number of weeks after the end of an advertising campaign:
\[ y = 3000 \times (3^{-0.1x}) \]
a. Graph the function for \( 0 \leq x \leq 60 \)
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Function Overview: The function indicates that as time (in weeks) increases after the advertising campaign, the sales \( y \) will decline exponentially.
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Behavior Analysis:
- At \( x = 0 \): \[ y = 3000 \times (3^0) = 3000 \text{ dollars} \]
- As \( x \to \infty \), \( y \) approaches \( 0 \), since \( 3^{-0.1x} \) decays toward zero.
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Key Data Points:
- Calculate \( y \) for a few key points. For example:
- \( x = 10 \): \[ y = 3000 \times (3^{-1}) = 3000 \times \frac{1}{3} = 1000 \text{ dollars} \]
- \( x = 20 \): \[ y = 3000 \times (3^{-2}) = 3000 \times \frac{1}{9} \approx 333.33 \text{ dollars} \]
- \( x = 30 \): \[ y = 3000 \times (3^{-3}) = 3000 \times \frac{1}{27} \approx 111.11 \text{ dollars} \]
- Calculate \( y \) for a few key points. For example:
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Graphing: The graph will start at 3000 dollars at \( x = 0 \), drop significantly as \( x \) rises, and asymptotically approach \( 0 \).
Given the graphical behavior and data points calculated, the correct choice represented from the options provided matches the description in part B:
- Graph C: shows the behavior correctly where it starts at 3000 and decreases sharply.
b. Calculate the sales 10 weeks after the campaign ended:
- We have already computed: \[ y(10) = 3000 \times 3^{-1} = 1000 \text{ dollars} \]
So, the weekly sales 10 weeks after the campaign ended is \($1000\).
c. Comment on "It pays to advertise" for this store.
Based on the provided model and calculations:
- The advertising campaign resulted in a high initial sales spike of $3000 immediately following the campaign. However, this model shows that the benefits of advertising are temporary, with sales declining to $1000 only 10 weeks later.
- Thus, while it initially pays to advertise by generating significant immediate revenue, the lasting impact appears minimal, as the sales trend suggests quickly diminishing returns over time after the campaign.
- In light of this analysis, it may be important for the store to consider strategies for sustaining sales after advertising, such as promotions, customer retention efforts, or ongoing marketing initiatives.