What occurs twice in a week, once in a year but never in a day?

There was a man he lives in a hotel each morning he presses the first floor button each evening if there is a person in the elevator he asks him to press the 10 floor button if there is no one in the elevator he takes the stairs why.

A professor thinks of two consecutive numbers between 1 and 10.
'A' knows the 1st number and 'B' knows the second number

A: I do not know your number.
B: Nor do I know your number.
A: Now I know.

What are the four solutions for this?

Speaking of rivers, a man calls his dog from the opposite side of the river. The dog crosses the river without getting wet, and without using a bridge or boat. How?

Its something that each of us devours,
Not just us but birds, beats, trees, and flowers,
Frets iron and nibbles steel,
Toil hard stones to meal,
Exterminates king, collapse town,
And blows the mountains down.

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

Find the number of squares in the below-given picture.

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

Can anyone tell me a word in the English dictionary which has a silent 'z'?

Can you solve the maths in the below-given picture equation?