Natasha makes an online purchase of 3 hardcover books for $19.95 each and 1 book on tape for $17.43. The site says that taxes paid by the customer are 7.25% of the total purchase price. Shipping charges are based on the following table:
| Amount of Purchase | Standard Shipping | Express Shipping |
| :----------------- | :---------------- | :--------------- |
| up to $50 | $5.10 | $7.00 |
| $50 up to $100 | $6.35 | $8.20 |
| $100 up to $200 | $7.80 | $11.60 |
| $200 and over | $10.50 | $16.45 |
Natasha selects standard shipping for her purchase, and the company bills her credit card $91.08 for the total of the online purchase. Determine if Natasha has been billed correctly for her purchase.
A. Natasha has been billed correctly.
B. Natasha has not been charged enough for her purchase.
C. Natasha has been overcharged by $1.85 for her purchase.
D. Natasha has been overcharged by $8.20 for her purchase.
Answer (2)
Natasha's subtotal was $77.28, tax was $5.60, and shipping was $6.35, totaling $89.23. She was billed $91.08, indicating that she has been overcharged by $1.85. Thus, Natasha has not been charged enough for her purchase.
;
Calculate the subtotal of the purchase: 3 × 19.95 + 17.43 = 77.28 .
Calculate the tax: 0.0725 × 77.28 = 5.60 .
Determine the shipping cost from the table: $6.35.
Calculate the total cost: 77.28 + 5.60 + 6.35 = 89.23 . Natasha has been over charged by $1.85 .
Explanation
Calculate the Subtotal First, we need to calculate the cost of the 3 hard cover books. Each book costs $19.95, so the total cost is: 3 × 19.95 = 59.85 Next, we add the cost of the book on tape, which is $17.43, to find the subtotal before tax and shipping: 59.85 + 17.43 = 77.28 So, the subtotal is $77.28.
Calculate the Tax Now, we calculate the amount of tax. The tax rate is 7.25% of the subtotal, so the tax amount is: 0.0725 × 77.28 = 5.6028 Rounding to two decimal places, the tax is $5.60.
Determine the Shipping Cost Next, we determine the shipping cost. The subtotal is $77.28, which falls in the range of $50 up to $100. Natasha selected standard shipping, so the shipping cost is $6.35 according to the table.
Calculate the Total Cost Now, we calculate the total cost by adding the subtotal, tax, and shipping cost: 77.28 + 5.60 + 6.35 = 89.23 So, the calculated total cost is $89.23.
Compare and Conclude Finally, we compare the calculated total cost ($89.23) with the billed amount ($91.08) to determine the difference: 91.08 − 89.23 = 1.85 The difference is $1.85. Since the billed amount is higher than the calculated total cost, Natasha has been overcharged by $1.85.
Examples
Imagine you're shopping online for clothes. You add items to your cart, and each item has a price. To figure out the total cost, you first add up the prices of all the items. Then, you calculate the sales tax by multiplying the subtotal by the tax rate. Finally, you add the shipping cost to get the final amount you'll pay. This is similar to Natasha's situation, where she bought books and had to calculate the total cost including tax and shipping. Understanding how to calculate these costs helps you manage your budget and avoid overspending when shopping online.
