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

A boy was locked in a room by some robbers. All that is in the room is a piano, a calendar, and a bed. The room is locked from the outside. What does he eat, drink, and how does he escape and get out?

There are three Athletes (John, Tarun and Harish) and their individual Coaches (Jacob, Meenaxi and Priyanka) standing on the shore.
No Coach trusts their Athlete to be near any other Coach unless they are also with them.
There is a boat that can hold a maximum of two persons.
How can the six people get across the river?

A man is walking down a road with a basket of eggs. As he
is walking he meets someone who buys one-half of his eggs
plus one-half of an egg.
He walks a little further and meets another person who buys
one-half of his eggs plus one-half of an egg.
After proceeding further he meets another person who buys
one-half of his eggs plus one half an egg. At this point, he
has sold all of his eggs, and he never broke an egg.
How many eggs did the man have to start with?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

In a university, a professor gave a set of three problems to the three brilliant students of his class. See the image for the questions.

Can you solve this picture maths equation?

What are the five permanent members of the UN Security Council?

a) France, Germany, Italy, Japan, United Kingdom
b) Canada, Mexico, Saudi Arabia, Turkey, United Arab Emirates
c) Brazil, India, Nigeria, South Africa, South Korea
d) China, France, Russia, United Kingdom, United States

I know a nine-letter word having only one vowel.
Do you ?

Two fathers and two sons decided to go to a shop and buy some sweets upon reaching. Each of them bought 1 kg of sweet. All of them returned home after some time and found out that they had 3kg of sweets with them.

They did not eat the sweets in the way, nor threw or lose anything. Then, how can this be possible?