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

In a competitive exam, each correct answer could win you 10 points and each wrong answer could lose you 5 points. You sat in the exam and answered all the 20 questions, which were given in the exam.
When you checked the result, you scored 125 marks on the test.

Can you calculate how many answers given by you were wrong?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

It's pretty hard to give up.
If you remove a part of it, you will be left with a bit.
Even if you remove another part, the bit still remains.
Remove one more and it still remains.

What is it?

In The 1st month of this year(the year 2013), I noticed that the date 13-1-13 (13 January 2013) is special.

This date is special as:

Date * Month = Year.

Can you figure out which year of this century has a maximum number of such dates?

There’s a one-story house in which everything is yellow. Yellow walls, yellow doors, yellow furniture. What colour are the stairs?

Solve the below puzzle by replacing the question mark with the correct number.

3 6 12

4 8 16

5 10 ?

How many minutes are there in Feb 2017?

Note: The shortest answer is the correct answer.

A Child was born in Lahore, Pakistan. Still, the child is not a Pakistani citizen. why?