Ruby will buy a total of 10 books, but she already has so many books on her bookshelf. Her bookshelf can hold 130 pounds. Now let's assume that every book on her bookshelf is exactly 2 pounds, and so are all 10 books she wants to buy. her book shelf is currenty holding 89 pounds worth of books. She wants to find out how many more books she can fit on ther shelf so she can buy that many. Bonus question, How many books are currently on her bookshelf?
To find out how many more books Ruby can fit on her bookshelf, we need to subtract the current weight of books from the maximum weight the shelf can hold.
Maximum weight the shelf can hold - Current weight of books = Available weight for new books
130 pounds - 89 pounds = 41 pounds
Since each book weighs 2 pounds, Ruby can fit 41/2 = 20.5 books on her shelf.
However, since we're dealing with whole books, Ruby can only fit 20 more books on her shelf.
Therefore, Ruby can buy 20 more books.
To answer the bonus question, currently there are 89/2 = 44.5 books on her bookshelf.
However, since we're dealing with whole books, Ruby currently has 44 books on her bookshelf.