Verses with the word fifties in the Old Testament (5 verses):

Exodus 18:21
Moreover thou shalt provide out of all the people able men, such as fear God, men of truth, hating covetousness; and place such over them, to be rulers of thousands, and rulers of hundreds, rulers of fifties, and rulers of tens:

Exodus 18:25
And Moses chose able men out of all Israel, and made them heads over the people, rulers of thousands, rulers of hundreds, rulers of fifties, and rulers of tens.

Deuteronomy 1:15
So I took the chief of your tribes, wise men, and known, and made them heads over you, captains over thousands, and captains over hundreds, and captains over fifties, and captains over tens, and officers among your tribes.

1 Samuel 8:12
And he will appoint him captains over thousands, and captains over fifties; and will set them to ear his ground, and to reap his harvest, and to make his instruments of war, and instruments of his chariots.

2 Kings 1:14
Behold, there came fire down from heaven, and burnt up the two captains of the former fifties with their fifties: therefore let my life now be precious in thy sight.