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

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

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

You have two rectangular wires.

Both of them have property that when you light the fire from one end , it will take 60 minutes to get completely burn.

However, they do not burn at consistent speed (i.e it might be possible 1st 20% burn in 50 minutes and 80% can burn in 10 minutes).

So how could you measure 45 minutes ?

Find the missing number in the image below.

You have a square. What you have to do is cut and reassemble the square such that you create a Red Cross sign that has the same volume as that of the square.

I left my campsite and hiked south for 3 miles. Then I turned east and hiked for 3 miles. I then turned north and hiked for 3 miles, at which time I came upon a bear inside my tent eating my food! What colour was the bear?

How can you leave a room with two legs and return with six legs?

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

What is black when you buy it, red when you use it, and gray when you throw it away?