Answer:
it depends
Explanation:
If the tradeoff between giants and elves is linear, then about 76 elves can be admitted. If it is non-linear, we need more information about the tradeoff.
For example, elves may fit in the spaces between giants in such a way that they take up proportionately less room. Or, elves may repel giants in such a way that they take up proportionately more room.
See the attached graph for some possibilities.
_____
The linear equation can be written as ...
g/160 + e/240 = 1
Then for g=109, we can solve for "e" as ...
109/160 + e/240 = 1
240(1 -109/160) = e = (3/2)(51) = 76.5
If the tradeoff is linear, 76 elves can be admitted.