Why is a river so rich ?

Mr. Buttons was all set to go to the village of Buttonland to meet his friend. So, he packed his bags and left for the village at 5 in the morning. Upon travelling on a road for miles, he came across a point where the road diverged into two. He was confused on which road to take. He gazed around and he saw two owls sitting on a branch. He thought he could ask for directions for the village from the two owls. So he went to the tree. There he saw a sign which read, "One owl always lies, and one is always truthful. They both fly away if you ask them more than 1 question."
Mr. Buttons was caught in the dilemma of what to ask? And from which owl to ask, since he only had one question. What should Mr. Buttons ask?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

Next Number in the Series,

5, 16, 49, 104, ?

Can you fill the blank with the correct number?

6 30 870 756030 _____

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

When can we add 2 to 11 and get 1 as the correct answer?

I cry without having a voice.
I fly without having wings.
I bite without having teeth.
I whisper without a mouth.

Who am I?

How can you spell "White of an egg" in one word?
Hint: I know you can spell coke, poke, and joke.

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?