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

While going to your grandmother's house, you counted Twenty houses on the right side. While returning back to your home, you counted Twenty houses on the left side.

How many houses are there between your home and your grandmother's home?

It is a nine-letter word.
The exact opposite of the phrase "friendly and outgoing"
It contains the word "over".
It starts will a vowel.

What is it?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

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?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

These types of puzzles are known as charades. What you have to do is to find two words that are referred to in the first stanza and the second stanza and put them together to form the third word in the third stanza.

Just for example, if my first refers to 'off' and my second refers to 'ice', then my whole will be the 'office'.

My first is present - future's past -
A time in which your lot is cast.

My second is my first of space
Defining people's present place.

My whole describes a lack of site -
A place without length, breadth, or height.

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?