Answer:
What coin doubles in value when half is deducted?
How is it possible to always find what your looking for in the last place you look?
The yellow house has yellow window, the red house has red windows, what colour windows does the green house have?
First I threw away the outside and cooked the inside then I ate the outside and threw away the inside. What did I eat?
There are two sisters: one gives birth to the other and she, in turn, gives birth to the first. Who are the two sisters?
Long and slinky like a trout, never sings till it's guts come out.