Do You See It?

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

When is the top of a mountain similar to a savings account?

A 3 digit number is such that it's unit digit is equal to the product of the other two digits which are prime. Also, the difference between it's reverse and itself is 396.

What is the sum of the three digits?

What 5-letter word typed in all capital letters can be read the same upside down?

Can you place three balls such that the equation shown in the picture holds true?

You can hear me, but you can't touch or see me.

What am I?

Suppose you are a girl candidate and sitting in an interview. Suddenly the interviewer asks you, 'What if one morning you wake up and find out that you are pregnant?

How will you reply to such a question?