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

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

I am quite hot but become too cold if you remove the first two letters. What am I?

Can you find out the total number of triangles in the given figure?

If you say my name, I will no longer exist. What am I?

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

Can you find the number?

We have shown you a regular water barrel as below. Without using any measuring device can you check if the barrel is more than half-filled or less than half-filled?

John was going on a jungle trip. He asked his wife to pack something to eat, something to drink and something to burn if he feels cold in the jungle. When John opens the backpack he found just one thing in the bag. What was it?

You are presented with three boxes. One of them has a red ball inside and the other two have a black ball inside each of them. You are asked to pick up the one with red ball and you pick one. Now, one of the other boxes is opened and it is found to have a black ball.

You are presented with a chance to change your box with the one that is left closed. Will you change your box? Why or why not?

An artist while painting a scenic beauty, decides to paint three layers of blue colour on the sky.

Which layer will go on the first?

John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?