Which number should replace the question mark?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

In the given figure, you can see that four match sticks are used to form a square. Can you form five squares by using six matches?

There are three identical triplets sisters. Demi is the oldest of them all and she always speaks the truth. Diana is the next one who is a liar always. Drew, the youngest of them all speaks both truth and lies randomly.

On a rainy day, a family friend Victor visited them. Since there were starkly identical, he was not able to recognize them. Thus to clarify, he asked one question to each one of them.

He started with the one standing on the left and asked, 'Which sister is in the middle of you three?' She answered, 'That's Demi.'

Then, he asked the one standing in the middle, 'What is your name?' She answered, 'I am Drew.'

Finally, he asked the one standing on the right, 'Who is standing in the middle?' She answered, 'She is Diana.'

Victor was left baffled. He asked the questions three times and received different answers every time.

Can you tell who was who?

Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

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?

I have no life, but I can die. What am I?

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

If an earthquake is 1 point higher on the Richter Scale than another earthquake which is actually 10 times stronger, how much stronger would an earthquake be if it was just half a point higher on the Richter scale?