How many times can you subtract the number two from the number fifty?

What has 13 hearts but no other organs?

What have one eye but still cannot see?

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

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

0 0 0 = 6
1 1 1 = 6
2 2 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

You can use any mathematical symbols in the space provided to make all above algebraic expressions true.

Suppose you are sitting in an interview and the interviewee asks you an aptitude question.

You have three buckets with a capacity of 4 litres, 8 litres and 10 litres and you have a large tank of water. Now you have to measure 3 litres of water precisely using those buckets. How will you do it?

I travel all around the world but always stay in the corner. What am I?

What number comes next in the series?

5 15 5 18 5 24 14 20 _