It is deaf, Dumb and Blind!!!

Still, always tells the truth. What is it?

Who always enjoys poor health?

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

We have four gears with below features=> Both Gear A and D has 60 teeth=> Gear B has 40 teeth=> Gear C has 20 teeth=> Every two minutes, Gear B makes 25 full turns.What is the relative speed of Gear A and Gear B?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

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

Can you make the number 24 by utilizing the numbers 1, 3, 4 and 6? You must use one number only one time and you can use mathematical operation symbols anytime anywhere.

What have one eye but still cannot see?

Before Mount Everest was discovered, what was the highest mountain in the world?

A number can be multiplied by multiple of nine
i.e 9 18 27 36 45 ...

and the resulting number consist of only one digit.

Can you identify the number ?