Final answer:
After applying a 50% discount to the original price of $80, the sale price of the toy rocket becomes $40. Adding the 5% sales tax of $2, Gwen paid a total of $42 for the toy rocket, making the correct answer d) $42.
Step-by-step explanation:
Calculating Total Cost After Discounts and Sales Tax
To answer the student's question "A toy rocket was originally priced at $80, but Gwen waited to buy it until the toy rocket was on sale for 50% off. If she paid 5% sales tax on the sale price, how much did she pay in total?", we first calculate the sale price after the discount is applied and then add the sales tax to this amount.
The original price of the toy rocket is $80. With a 50% discount, the sale price is calculated by multiplying the original price by 50% (or 0.5). So, $80 × 0.50 = $40.
Next, we calculate the sales tax on the sale price. Convert the sales tax rate to a decimal by dividing by 100 (5% becomes 0.05) and then multiply it by the sale price. Thus, the sales tax for the toy rocket is $40 × 0.05 = $2.
Finally, we add the sales tax to the sale price to find Gwen's total payment:
$40 (sale price) + $2 (sales tax) = $42 (total price).
Therefore, the correct answer is d) $42. Gwen paid a total of $42 for the toy rocket including sales tax.