Can you replace the question mark with the correct letter?

6 + 6 + 6 = N
7 + 7 + 7 = E
8 + 8 + 8 = R
0 + 0 + 0 = ?

If all Goats are Sheep and all Sheep are Deers, are all Deers Goats ?

Prove that twice of ten is the same as twice of eleven.

A King wants to send the diamond ring to his girlfriend securely. He got multiple locks and their corresponding keys. His girlfriend does not have any keys to these locks and if he sends the key without a lock, the key can be copied in the way. How can King send the ring to his girlfriend securely?

What does this rebus puzzle means ?

Out of three Friends John, Jacob and Jonny one of them is a king, one is a bureaucrat, and one is a Spy.

The king always tells the truth, the bureaucrat always lies, and the Spy can either lie or tell the truth.

John says: Jonny is a bureaucrat
Jacob says: John is a king
Jonny says: I am a Spy

Tell me, Who is the king, who is the bureaucrat, and who is the Spy?

Find the next number in the series

12, 20, 40, 72, 116, 172 ?

Why Wine Glass Stem is so long?

During which month do people sleep the least?

Solve the below puzzle by replacing the question mark with the correct number.

3 6 12

4 8 16

5 10 ?