Name a key which is hardest to turn.

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

What is more useful when it is broken?

How can you make a TV, a bed, a dog, and a car liquid?

He loves to dance, twist and prance, he shakes his tail, and as a way he sails, wingless he flies into the sky. What is he?

What number should come in place of the question mark below?

You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?

You have two jars of chocolates labelled as P and Q. If you move one chocolate from P to Q, the number of chocolates on B will become twice the number of chocolates in A. If you move one chocolate from Q to P, the number of chocolates in both the jars will become equal.

Can you find out how many chocolates are there in P and Q respectively?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.