Question

how many floating rins arranged in sternum

Answer 1

A rib is said to be "floating" if it does not attach to the sternum (the breast bone) or to another rib. There are usually 12 pairs of ribs in all. Each pair of ribs is attached to the building blocks of the spine (the vertebrae) in the back.

Answer 2

Actually the are 12 floating rins.

We know that ribs are known as floating.

They are 12 in number and are joined to back bone or you can say spinal cord.

They are responsible for holding various organs, like lungs, etc.