why number 8549176320 is one of a kind?

Two boys wish to cross a river. The only way to get to the other side is by boat, but that boat can only take one boy at a time. The boat cannot return on its own, there are no ropes or similar tricks, yet both boys manage to cross using the boat.

How?

One of the leprechaun is missing if you see the two pictures attached to this question. Where did he go? When he comes back, do you know where has he been?

There is a unique number which when multiplied by any number from 1 to 6, we will get the new number that contains the same digits only.

Can you find that number?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

Krish is 45 years old and his mother Crishtina is 73 years old.

Can you find out how many years ago, his mother was three times his age?

If a shopkeeper can only place the weights on one side of the common balance. For example, if he has weights 1 and 3 then he can measure 1, 3 and 4 only. Now the question is how many minimum weights and names of the weights you will need to measure all weights from 1 to 1000? This is a fairly simple problem and very easy to prove also.

Until it is measured, not known. Yet how you miss it when it has gone. What is it?