What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

If,

20 % 5 = 24

21 % 7 = 33

42 % 6 = 67

Then;

66 % 6 = ?

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

The more it dries, the wetter it becomes. Can you tell what it is?

The captain of a ship is telling you an interesting story and then poses a question. He says, “I have travelled the oceans far and wide. One time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly. Can you tell me how that was possible?”

what does this picture(rebus) riddle means ?

Solve The below Equation:

ALFA + BETA + GAMA = DELTA

Can you find the company name in the pictogram below?

13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

Can you replace the question mark with the correct number?