Answer:
Jill had $136.50 before buying the book.
Explanation:
Let x be the total amount that Jill had
Then 12% of x is 0.12x
Jill was left with $120.12 after buying the book
Subtracting the cost of book from the total amount will given us the remaining amount.
Which means
Hence,
Jill had $136.50 before buying the book.