For each other, the web site applies a 7.7% sales tax to the price of the cards, plus a one-time mailing fee of $5.95. Based on the information in the table, what will be the total cost for an order for 280?

Answer:
Total cost for an order of 280 cards = $201.96
Step-by-step explanation:
Total number of cards to be ordered = 280
This can be done in a way that buy 100 cards twice and 40 cards twice.
280 = 100 + 100 + 40 + 40
So, price in dollars for 100 cards if bought two times = 2 × 65
= $130
And, price in dollars for 40 cards if bought two times = 2 × 26
= $52
Hence, total cost of buying 280 cards = 130 + 52 = $182
Sale tax applied on the price of cards = 7.7%
Total cost after applying sales tax = 182 + 7.7% of 182
⇒ Total cost = 182 + 0.077 × 182
⇒ Total cost = 182 + 14.014
⇒ Total cost = $196.014
Also, One time mailing fee of $5.95 is also applied on the order.
⇒ Total cost for an order of 280 cards = 196.014 + 5.95
= $201.96