What has one letter and starts with an E?

A mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.
Where's the father?

Which is faster, Heat or Cold ? Explain.

Can you write down eight eights so that they add up to one thousand?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

The more you take me, the more you leave me behind.
Who Am I?

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

how come the second man dies?

A man has eighty-one cows ( numbered 1,2,3...81 as such). The beauty is that cow no. 1 gives 1ltr of milk, cow no. 2 gives 2ltrs of milk and so on. The man wants to equally distribute the cows among his nine sons so that each one of them gets the same quantity of milk.

What Deficiency does the below rebus represent?

VIT_MIN