A book costs d dollars.

Which of the following expressions represents the total cost if Jill purchased three books?

The total amount paid by Jill = $ (3 d)

Step-by-step explanation:

Here, the cost of 1 book = $ d

Now, the number of books purchased by Jill = 3

So, the total cost of 3 books = 3 x (Cost of 1 book)

= 3 x ($d) = 3 d

So, if Jill purchased 3 books, the total amount paid by her = $ (3 d)