Why is the Hole below a Lock?

Can you count the number of triangles in the given picture?

Things are just as they seem, right? Well, check again.
Can you count the number of tigers in this picture ?

If in a code language, DISTANCE is written as IDTUBECN and DOCUMENT is written as ODDVNTNE, the how will THURSDAY be coded as in the same language?

In the image below, you can see two glasses and two matchsticks.You need to move four matchsticks in such a manner that the crosses come inside the glasses. Note: you cannot move the crossed.

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

You have two strings whose only known property is that when you light one end of either string it takes exactly one hour to burn. The rate at which the strings will burn is completely random and each string is different.

How do you measure 45 minutes?

I am an eight letter word and I am a computer terminology.
The second, third and fourth letters make an animal.
The fourth, fifth, sixth, seventh and eighth letters make a weapon.
The first, second, third and fourth letters can be taken as an outcome of any exam.
The fifth, sixth, seventh and eighth letter combine to form a high end typing software.

Can you tell who am I ?

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?