What happened when the wheel was invented?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

Can you find out the remainder when 3^300 is divided by 5?

I am 5 letters long.
My first two tell you who I am
My first 3 could be a medicine
My last three reversed could be a young boy.
My 4th, 3rd and 2nd in that order could be a fruit drink.
If you have me you may hang me round your neck
WHAT AM I ?

French Police inspects a room where there are no windows, no doors, no tables and is almost empty expect there is just a puddle of water. They found a dead man who obviously hung herself from the ceiling, but they are not able to figure out how this had happened.

John and Jacob entered the crime scene and easily able to solve the case.

How did the man die?

If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

We can be boring,Or interesting.
We can be long,Or short.
We can have pictures,Or just words.
Many love us,But many also hate us.
What are we?

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?

Find The Missing Number In the Sequence.
6 25 64 ? 32 1