I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

Given that

(78)^9 = 6
And (69)^4 = 11

Can you find out

(99)^2 =?

(Note: This is Logical, not Mathematical)

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?

Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

Identify the hidden meaning behind this picture?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

Nodes are shown below and you need to connect them based on the following rule: Every node can be connected to the number of nodes inside them, i.e. the first node there is a value of 1 which indicates that the first node can connect to exactly one node only.Can you do it?

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

How high do you have to count before you use the letter “a” in the English spelling of the whole number?