Find the next number in the series below

21 32 54 87 131 ?

Suppose we lay down two cups in front of you. One of the cups is filled with tea and the other one with coffee. Now we ask you to take a spoonful of tea and mix it with the coffee. At this moment, the coffee cup has a mixture of tea and coffee. You have to take that mixture (spoonful) and add it back to the tea.

Can you now tell if the cup of coffee has more tea or the cup of tea has more coffee?

I guess 76.8% of readers will like this riddle.

What's the least number of people should read this post?

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.

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

Which city is three-fifths chick two third cat and 50% goat?

How can you leave a room with two legs and return with six legs?

How many triangles can you find in this given picture?

Can you identify if it's a murder or a suicide ?