How old was Joshua when he died?

Answer: 110

Joshua son of Nun died at 110 and was buried in his inheritance at Timnath-serah in the hill country of Ephraim.

“Some time later, Joshua son of Nun, the servant of the LORD, died at the age of 110. And they buried him in the land of his inheritance, at Timnath-serah in the hill country of Ephraim, north of Mount Gaash.”— Joshua 24:29-30 (BSB)