Why is a river so rich ?

During which month do people sleep the least?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

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?

Why Wine Glass Stem is so long?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

Prove that the below maths equation is true.

8 + 8 = 91

Two guards were guarding the camp.Guard-1 was looking towards the south to make sure no threat is coming from the road.Guard-2 was looking at the north to make sure no threat is coming from the top. Suddenly Guard-1 ask the Guard-2 why he is smiling?How Guard-1 knows that Guard-2 is smiling?

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

What does the below image rebus riddle means ?