Find the number of squares in the below picture

What do you see in the image below

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

Can you decipher the following common phrase?

T M C
A U O
H S M
W T E

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

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?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

All of Jacob's shoes are red except two.
All of Jacob's shoes are green except two.
All of Jacob's shoes are yellow except two.

How many shoes does Jacob have?

Women do it once a year after they turn 19 but men get to do it only once in a lifetime. What is it?