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

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 a shopkeeper can only place the weights on one side of the common balance. For example, if he has weights 1 and 3 then he can measure 1, 3 and 4 only. Now the question is how many minimum weights and names of the weights you will need to measure all weights from 1 to 1000? This is a fairly simple problem and very easy to prove also.

You have two buckets - one holds exactly 5 gallons and the other 3 gallons. How can you measure 4 gallons of water into the 5 gallon bucket?

(Assume you have an unlimited supply of water and that there are no measurement markings of any kind on the buckets.)

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

What can go up a chimney down, but can’t go down a chimney up?

What has one letter and starts with an E?

There is something which you can be arrested for attempting but not for successfully completing.

I have an eye but still cannot see.

Who am I?

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10