Question 2 Winona and Takoda are shopping for a present for their mother. The chart shows several possible presents. There is no sales tax in the state where they live. Present Cost ($) Discount (%) Total Paid ($) Power tools d dollars 15% Water skis d + 15 dollars 25% Jewelry d – 15 dollars 10% Write two expressions in terms of d to show how much Winona and Takoda would pay in total if they bought their mother the set of power tools. What does the expression 0.90(d – 5) refer to? How do you know? How else could this expression be written? Choose a value for d that is greater than $25 and less than $100. Calculate the total cost of each of the possible presents for the value you chose. Then write a short paragraph telling Winona and Takoda which present they should buy and explaining why.

3 answers

To calculate the total cost Winona and Takoda would pay for the presents listed, we need to first develop the expressions for the power tools and then evaluate each present using a specific value for \(d\).

Expressions for Total Cost

  1. Power Tools:

    • Cost before discount: \( d \)
    • Discount: \( 15% \) of \( d \) = \( 0.15d \)
    • Total Paid after discount: \[ d - 0.15d = 0.85d \]
  2. Total Paid for the power tools: \[ 0.85d \]

Expression Analysis

The expression \( 0.90(d - 5) \):

  • This expression calculates the total cost after applying a discount. Specifically:
    • First, \( d - 5 \) implies that there's an initial reduction of $5 from the original cost \(d\).
    • Then, \( 0.90 \) indicates a 10% discount is applied to the remaining amount.

This suggests a total amount of \( d - 5 \) before a final 10% discount is taken, resulting in paying 90% of that adjusted cost.

This expression could also be written as: \[ 0.90d - 4.5 \]

Chosen Value for \(d\)

Let’s select \( d = 40 \) (which is greater than $25 and less than $100) and calculate the total cost for each present.

  1. Power Tools: \[ 0.85(40) = 34 \]

  2. Water Skis:

    • Original cost: \( d + 15 = 40 + 15 = 55 \)
    • Discount: \( 25% \) of \( 55 = 0.25(55) = 13.75 \)
    • Total Paid: \[ 55 - 13.75 = 41.25 \]
  3. Jewelry:

    • Original cost: \( d - 15 = 40 - 15 = 25 \)
    • Discount: \( 10% \) of \( 25 = 0.10(25) = 2.5 \)
    • Total Paid: \[ 25 - 2.5 = 22.5 \]

Summary of Total Costs

  • Power Tools: $34
  • Water Skis: $41.25
  • Jewelry: $22.5

Recommendation Paragraph

Based on the total costs calculated, I recommend Winona and Takoda buy the jewelry for their mother, as it totals only $22.5, making it the most affordable option. While the power tools are a worthwhile gift at $34, selecting the jewelry allows them to save more money while still giving a thoughtful present. The water skis, even though fun, are the most expensive at $41.25, which is less cost-effective. Thus, jewelry stands out as a loving and considerate gift that fits comfortably within their budget.

So what are the answers?

Here’s a summary of the answers to the problem:

Expressions for Total Cost

  1. Power Tools Total Cost: \[ 0.85d \]

What the Expression \( 0.90(d - 5) \) Refers To

  • Meaning: This expression calculates a total payment after deducting $5 from \(d\) and then applying a 10% discount on that reduced amount.
  • Alternate Form: It can also be expressed as: \[ 0.90d - 4.5 \]

Chosen Value for \(d\)

  • Value Chosen: \( d = 40 \)

Calculated Total Costs for Each Present

  1. Power Tools: \[ 34 \text{ dollars} \] (calculated as \(0.85 \times 40\))

  2. Water Skis: \[ 41.25 \text{ dollars} \] (calculated as \(55 - 13.75\))

  3. Jewelry: \[ 22.5 \text{ dollars} \] (calculated as \(25 - 2.5\))

Recommendations

  • Best Option: Jewelry at $22.5 (the most affordable and thoughtful gift).
  • Power Tools Total: $34
  • Water Skis Total: $41.25

Summary

Winona and Takoda should purchase jewelry for their mother as it's the least expensive option at $22.5 while still being a meaningful gift.