'Fifteen' in the Bible

You shall till the land for him, you, and your sons, and your servants; and you shall bring in [the fruits], that your master's son may have bread to eat: but Mephibosheth your master's son shall eat bread always at my table." Now Ziba had fifteen sons and twenty servants.

There were a thousand men of Benjamin with him, and Ziba the servant of the house of Saul, and his fifteen sons and his twenty servants with him; and they went through the Jordan in the presence of the king.