Question

One month Miko bought two books at a used book store for a total of $2. Over the next few months, she bought four books for a total of $5, six books for a total of $7, and eight books for a total of $10. Is the cost proportional to the number of books purchased?

A) Yes
B) No

Answer 1

Miko's cost per book is not consistent across her purchases, indicating that the cost is not proportional to the number of books bought. The cost per book varies with each purchase; hence, the answer is No, the cost is not proportional.

Step-by-step explanation:

The question is whether the cost is proportional to the number of books purchased by Miko. To determine this, we can compare the ratios of the cost to the number of books for each purchase. For proportionality, these ratios should be constant.

• First Purchase: 2 books for $2 gives us a ratio of $1 per book.
• Second Purchase: 4 books for $5 gives us a ratio of $1.25 per book.
• Third Purchase: 6 books for $7 gives us a ratio of approximately $1.17 per book.
• Fourth Purchase: 8 books for $10 gives us a ratio of $1.25 per book.

Since the ratios are not the same for each purchase, the cost is not proportional to the number of books. So, the answer is B) No.