Final answer:
Jeffrey spent a total of $57 on books and magazines combined, by purchasing 4 books at $9 each and 7 magazines at $3 each and then adding the costs together.
Step-by-step explanation:
Jeffrey bought 3 books about plants and 1 book about fish. He also bought 7 science magazines. We need to calculate the total cost of his purchases. Each book costs $9 and each magazine costs $3.
- To find the total cost of the books, multiply the number of books by the cost of each book:
- 3 plant books + 1 fish book = 4 books
- 4 books × $9 per book = $36
- For the magazines, multiply the number of magazines by the cost of each magazine:
- 7 magazines × $3 per magazine = $21
- Now, add the cost of books and magazines together to get the total amount Jeffrey spent:
- $36 for books + $21 for magazines = $57
Thus, Jeffrey spent a total of $57 on books and magazines combined.