What numbers should go on the bottom line?
3 6 9 15
8 2 10 12
11 8 19 27
19 10 29 39
? ? ? ?

Who always enjoys poor health?

There’s a one-story house in which everything is yellow. Yellow walls, yellow doors, yellow furniture. What colour are the stairs?

You know three triplets: Frank John and Wayne (need to return your money). Frank always tells the truth while John and Wayne always lie. You meet one of them on the road and can ask him a three-word question.
Which question, will you ask?

Which Travels Faster? Solve below famous picture riddle:

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

I cannot talk, but I always reply when spoken to. What am I?

An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

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

3 6 12

4 8 16

5 10 ?