Question 1

The average amount that Mia spent per book for the 4 books is 3, $15, and $80.

Mia purchased 4 books, three of which were priced at $15 each. The average cost per book is derived from the total amount spent, which is $80, divided by the number of books, resulting in an average of $20 per book.

A) 4 and $80 only

This option is incorrect because it only mentions the number of books and the total amount spent without referencing the individual book prices or the average cost. The average cost per book is a critical aspect of the question.

B) 4, 20%, and $80 only

This option is incorrect as it includes the number of books and the total amount but fails to mention the price of the individual books. The presence of the 20% discount is also irrelevant for calculating the average cost per book.

C) 3, $15, and 20% only

This option is incorrect because, while it correctly identifies three books priced at $15, it does not include the total amount spent of $80 or the total number of books purchased, which is essential for calculating the average.

D) 3, $15, and $80 only

This option is correct as it includes three books priced at $15 and the total amount spent of $80. These elements are necessary for determining the average cost per book, which is essential for answering the question accurately.

E) 3, 4, $15, and $80

This option is incorrect; while it includes relevant details, it is overly inclusive. The question only requires an average calculation, which can be accurately derived from the components found in option D.

Conclusion

The correct answer is option D because it succinctly captures the necessary elements to calculate the average amount spent per book: the number of specific books, their price, and the total expenditure. All other options either omit critical information or include unnecessary details, failing to address the average cost per book directly.