Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

The chance of Mr John winning the lottery is 10%. All participants lined up and Mr John is 4th in the row. The first three participants lose the lottery.

What is the chance of Mr John now?

Who always enjoys poor health?

What's the next in the series?

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

Look at me. I can bring a smile to your face, A tear to your eye, Or even a thought to your mind. But, I can't be seen. What am I?

Imagine you are in a room with no windows or doors. How will you get out?

What has one letter and starts with an E?

What does this mathematical rebus means ?

Prove that the below maths equation is true.

8 + 8 = 91

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