How many loaves of barley bread did Elisha use to feed a hundred men?

Answer: Twenty

A man brought Elisha twenty loaves of barley bread, and Elisha fed a hundred men with it.

“Now a man from Baal-shalishah came to the man of God with a sack of twenty loaves of barley bread from the first ripe grain. “Give it to the people to eat,” said Elisha.”— 2 Kings 4:42 (BSB)