How many beads are usually found on a rosary?

The commonest have five decades with one larger extra bead before each decade, a total of 55 beads.
https://en.wikipedia.org/wiki/Rosary

I remember mine from my childhood days had 60.
No idea how many times I counted them but there was definitely 60.

ro·sa·ry ( P ) Pronunciation Key (rz-r)
n. pl. ro·sa·ries
Roman Catholic Church.
A form of devotion to the Virgin Mary, chiefly consisting of three sets of five decades each of the Hail Mary, each decade preceded by the Lord's Prayer and ending with a doxology.
One of these sets of decades.

A string of beads of 5 or 15 decades on which these prayers are counted.
Similar beads used by other religious groups.


Rosary, Rosary Beads
General Information
A rosary is a circular string of beads used by Roman Catholics for counting prayers. The term is also applied to the prayer beads used by Buddhists, Hindus, and Muslims.

In the Western church, the rosary commonly consists of 5 (originally 15) decades, or sets of 10 beads, for the recitation of the Hail Mary (Ave Maria), separated by a single bead (total of 55) for the recitation of the Our Father (Paternoster, or Lord's Prayer). The Glory Be to the Father (Gloria Patri) is generally said after each decade. During the recitation of the prayers, meditation on a series of biblical themes, called the joyous, sorrowful, and glorious mysteries, is recommended.

A feast of the Rosary is kept on October 7, the anniversary of the Christian victory over the Muslim Turks at Lepanto (1571).

mb-soft.com/believe/txh/rosary.htm no longer exists
https://www.simplycatholic.com/where-did-the-rosary-originate

Buddhist rosaries generally have 108 beads.

"Conventional Buddhist tradition counts the beads at 108, signifying the mortal desires of mankind. "

https://en.wikipedia.org/wiki/Buddhist_prayer_beads

RC rosary has 60 beads.

The word 'bead' actually comes from a word 'bed' meaning prayer in Old English. When you counted your prayers, the little things on the rosary helped you to keep count, and the name transferred over from the prayer to the little marker.

50 + 10 = 60 beads

"A five-decade rosary contains five groups of ten beads (a decade), with additional large beads before each decade."

https://en.wikipedia.org/wiki/Rosary