Decode this picture on T-Shirt and tell what it says ?

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?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

I have some blue and red sock in my drawer. I have a total of 4 socks. I pick 2 socks and the chance that I get a pair of red socks is 1/2.

What is the chance of picking a pair of blue socks?

I look at you, you look at me I raise my right, you raise your left. What am I?

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

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

Which point will the car reach to go out?

A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?

Find the missing letter in the last circle logically in the given below picture.