Answer:
the answer would be 90
Explanation:
100 giants fills 5/8 (100/160) of the theater leaving 3/8 of the theater for the elves.
3/8 times 240 elves is 90 elves.
If there were 150 elves that would also be 5/8 filled plus the original 5/8 filled with 100 giants! Some elves might suffer!!!