What is black when you buy it, red when you use it, and gray when you throw it away?

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

I am soft and cuddly that soothe your heart. But, If you pick my last name I am going to tear you all apart. Who am I?

John bought a new car. He has a habit of eating ice cream from a particular ice cream shop while returning home from office. Whenever, he eats strawberry ice cream, he faces no problem. But whenever, he eats chocolate ice cream, the car starts giving problem. At first, he thinks, it is just a co-incidence but when this awkward incident happens for 3-4 times, he reports this problem to the company.

The mechanic of the company checks but finds no problem at all. The next day, when he stops by to eat chocolate ice cream, the car again starts giving problem.

Can you find the possible reason?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

what does the below rebus mean?

Women do it once a year after they turn 19 but men get to do it only once in a lifetime. What is it?

What makes this number unique: 8,549,176,320?

Arrange the numbers 1, 2, 3, 4, 5, 6, 7, 8 and 9 above and below the division line in a manner that the thus formed fractions equal to 1/3.

(You can use one number only once)

12345 a famous South Indian actor
567 is a path in jumbled form
8 & 10 are same letters
9 is one among the first six alphabets.
WHO AM I?