I have an eye but still cannot see.

Who am I?

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

In the image below, can you find the value of an angle(y)

Complete the following series. It.s very logical:

1, 4, 5, 6, 7, 9, 11, __?

I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

I am thinking of a five-digit number such that:
The first and last digits are the same, their submission is an even number and multiplication is an odd number and is equal to the fourth number. Subtract five from it and we obtain the second number. Then divide into exact halves and we get the 3rd number.

What number I am thinking of?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

John is found dead in a bare field. Nobody killed John,
John did not commit suicide.

Inspector Jacob found a bag just a few meters away from John which could save his life. What was in the bag?

A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?

Count the number of balls in picture below: