If a hen and a half lays an egg and a half in day and a half, how many eggs will six hens lay in nine days?
Assuming there's no "gotchas!" with things like how half an egg could be laid etc. the answer is:
If 1.5 hens lay 1.5 eggs in 1.5 days, then 1 hen will lay 1 egg in 1.5 days. 9 days is 6x1.5 day periods, so the 6 hens will each lay 6 eggs, for a total of 36 eggs.