Do this work IF some one do I will make him brainliest if correct do it in rough book

All per-unit concepts rely on ratios, meaning, to provide a type of measurement

Bob is putting books on a shelf and takes a break after filling 18 1/2 inches on the book shelf. the book shelf is now 2/3 full. how long is the entire bookshelf?

Aye asap pls ! markin da brainiest too ! btw da step choices are all add, distribute, divide, n subtract