Slenda makes an online purchase of 4 picture frames for $12.95 each and 4 mats for $5.89 each. The site says that taxes paid by the customer are 6.5% 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 |
Slenda selects express shipping for her purchase and the company bills her credit card $91.86 for the total of the online purchase. Determine if Glenda has been billed correctly for her purchase.
A. Glenda has been billed correctly.
B. Glenda has not been charged enough for her purchase.
C. Glenda has been over charged by $3.40 for her purchase.
D. Glenda has been over charged by $3.80 for her purchase.
Answer (1)
Calculate the cost of the picture frames: 4 × $12.95 = $51.80 .
Calculate the cost of the mats: 4 × $5.89 = $23.56 .
Calculate the total cost: $51.80 + $23.56 + ( 0.065 × ( $51.80 + $23.56 )) + $8.20 = $88.4584 .
Determine the overcharge amount: $91.86 − $88.4584 = $3.4016 . Slenda has been over charged by $3.40 for her purchase.
Explanation
Calculate the cost of the picture frames First, we need to calculate the cost of the picture frames. Since Slenda bought 4 frames at $12.95 each, the total cost for the frames is:
Cost of frames 4 × $12.95 = $51.80
Calculate the cost of the mats Next, we calculate the cost of the mats. Slenda bought 4 mats at $5.89 each, so the total cost for the mats is:
Cost of mats 4 × $5.89 = $23.56
Calculate the total purchase price Now, we find the total purchase price by adding the cost of the frames and the cost of the mats:
Total purchase price $51.80 + $23.56 = $75.36
Calculate the sales tax The sales tax is 6.5% of the total purchase price, so we calculate the sales tax as follows:
Sales tax 0.065 × $75.36 = $4.8984
Determine the shipping cost Since the total purchase price is $75.36, which falls in the range of $50 up to $100, the express shipping cost is $8.20.
Calculate the total cost Now, we calculate the total cost by adding the total purchase price, sales tax, and shipping cost:
Total cost $75.36 + $4.8984 + $8.20 = $88.4584
Compare the calculated total cost with the billed amount The company billed Slenda $91.86. To determine if she was billed correctly, we subtract the calculated total cost from the billed amount:
Difference in cost $91.86 − $88.4584 = $3.4016
Conclusion Since the difference is $3.4016, Slenda was overcharged by approximately $3.40.
Examples
When shopping online, understanding how the total cost is calculated—including item prices, taxes, and shipping fees—helps you verify whether you're being billed correctly. By breaking down each component of the purchase, you can compare your calculations with the company's bill. This skill is useful for budgeting, spotting errors, and making informed purchasing decisions, ensuring you're not overpaying for your items. For example, if you buy multiple items, calculate the subtotal, apply the sales tax rate, determine shipping costs based on the subtotal, and then add everything together to confirm the final amount.
