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

Can you solve this picture maths equation?

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

Astrology starts with the alphabet A, Biology starts with B, Psychology with P and Limnology with L.

Can you find an "ology" that begins with a P?

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

Can you solve the photo plexer logic ?

What 5-letter word typed in all capital letters can be read the same upside down?

You can hear me, but you can't touch or see me.

What am I?

If two's company, and three's a crowd, then whats four and five ?

A boy was driving a car, a girl took a lift from her. She asked his name. The boy said - my name is hidden in my car’s number, find it if you can. After this, she got down Car number was [ WV733N ] Can you guess the name now?