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?

Find the missing number in the sequence below:

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

Can you divide numbers from 1 to 9 (1 2 3 4 5 6 7 8 9) into two groups so that the sum of the numbers of each group is equal?

Note: 9 cannot be turned over to make it 6.

A man dies of old age on his 25 birthday. How is this possible?

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

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

John gave half of the apples he had plus one more to Jacob. He gave half of the remaining ones plus one more to James. Now, John was left with just one apple.

Can you find out how many did he have in the beginning?

I can write cow in 13 letters.

Can You?