Question

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, 15
water skis, d+15, 25%
jewelry, d-5, 10%
Write two expressions in terms of d to show how much Winona and Takoda
would pay in total if they buy their mother the set of power tools. keep your answer short

Answer 1

What does the expression 0.90(d – 5) refer to? How do you know? How else
could this expression be written? keep answer short

Answer 2

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. keep answer short

Answer 3

If Winona and Takoda buy the power tools, the cost is \( d \) and the discount is \( 15 \).

The total paid for the power tools is:

\[
\text{Total paid} = d - 15
\]

Thus, the expression for the total paid for the power tools is:

\[
d - 15
\]

This is the only expression needed since they only have one present (power tools) being considered.

Answer 4

The expression \( 0.90(d - 5) \) refers to the total cost after a 10% discount on the jewelry, which has an original cost of \( d - 5 \).

You can know this because \( d - 5 \) reflects the cost of the jewelry before the discount, and multiplying by \( 0.90 \) gives the price after applying the 10% discount (100% - 10% = 90%).

This expression can also be written as:

\[
\frac{90}{100}(d - 5) \quad \text{or} \quad 0.9(d - 5)
\]

Both forms are equivalent.

Answer 5

Let's choose \( d = 30 \).

Now, we'll calculate the total cost for each present:

1. **Power Tools**:
\[
\text{Total} = d - 15 = 30 - 15 = 15
\]

2. **Water Skis**:
\[
\text{Original cost} = d + 15 = 30 + 15 = 45
\]
\[
\text{Discount} = 25\% \text{ of } 45 = 0.25 \times 45 = 11.25
\]
\[
\text{Total} = 45 - 11.25 = 33.75
\]

3. **Jewelry**:
\[
\text{Original cost} = d - 5 = 30 - 5 = 25
\]
\[
\text{Discount} = 10\% \text{ of } 25 = 0.10 \times 25 = 2.5
\]
\[
\text{Total} = 25 - 2.5 = 22.5
\]

### Summary of Total Costs:
- Power Tools: $15
- Water Skis: $33.75
- Jewelry: $22.50

### Recommendation:
Winona and Takoda should buy the power tools for $15. This option is not only the cheapest but also offers good value for a useful present. The jewelry and water skis are significantly more expensive, and the power tools would likely be appreciated as a practical gift for their mother.