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.
2 answers
1) Total Paid with a 15% discount:
Total Paid = d - 0.15d = 0.85d
2) Total Paid without a discount:
Total Paid = d
The expression 0.90(d - 5) refers to the total paid when there is a 10% discount subtracted from the original cost (d), and a further $5 reduction. The expression can also be written as 0.90d - 4.5.
Let's choose d = $50 as a value that is greater than $25 and less than $100.
For power tools:
Total Paid with a 15% discount = 0.85 * 50 = $42.50
Total Paid without a discount = $50
For water skis:
Total Paid with a 25% discount = 0.75 * (50 + 15) = $44.25
For jewelry:
Total Paid with a 10% discount = 0.90 * (50 - 15) = $31.50
Based on the calculations, I would suggest that Winona and Takoda buy their mother the set of power tools. The total cost of the power tools is $50, and since there is no discount for this present, they only have to pay the full price. The water skis have a 25% discount, but the jewelry has a 10% discount. In terms of cost, the power tools would be the most expensive option, but it would be a gift that their mother might find more useful and long-lasting compared to water skis or jewelry.