Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

What word is pronounced the same if you take away four of its five letters?

An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

The more it dries, the wetter it becomes. Can you tell what it is?

What word is identified by the below rebus?

Your Your Your Your Your
Your Your Your Your Your

He loves to dance, twist and prance, he shakes his tail, and as a way he sails, wingless he flies into the sky. What is he?

If an earthquake is 1 point higher on the Richter Scale than another earthquake which is actually 10 times stronger, how much stronger would an earthquake be if it was just half a point higher on the Richter scale?

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

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 ?