What's the next in the series?

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

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?

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

Which point will the car reach to go out?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

You throw me out when you want to use me and you take me in when you don't want to use me.

Who Am I?

The doctor prescribed you to take one pill from the bottle every half an hour. The bottle is now left with only three pills.

How long do you think you have before you run out of pills?

A Car driver was heading down a street in Washington. He went right past a stop sign without stopping, he turned left where there was a 'no left turn' sign and he went the wrong way on a one-way street. Then he went on the right side of the road past a cop car. Still, he didn't break any traffic laws. Why not?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?