Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

Two friends decide to get together; so they start riding bikes towards each other. They plan to meet halfway. Each is riding at 6 MPH. They live 36 miles apart. One of them has a pet carrier pigeon and it starts flying the instant the friends start traveling. The pigeon flies back and forth at 18 MPH between the 2 friends until the friends meet.

How many miles does the pigeon travel?

If eleven plus two equals one, what does nine plus five equal?

A train leaves from point A for point B at 80 mph. After half an hour, another train leaves from point B for point A at 60 mph.

Which of the trains will be farther from point A when they meet ?

What am I?

Prove that the below maths equation is true.

8 + 8 = 91

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive,

What is it?

what does this picture(rebus) riddle means ?