How can you make number one disappear by adding something to it?

2, 3, 5, 9, 17, _ What is the next number in the sequence?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

Why is the Hole below a Lock?

The measurement of time, That can't be found on a clock, But can be looked upon on a map.

Who is He ?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

There is a box in which distinct numbered balls have been kept. You have to pick two balls randomly from the lot.

If someone is offering you a 2 to 1 odds that the numbers will be relatively prime, for example
If the balls you picked had the numbers 6 and 13, you lose $1.
If the balls you picked had the numbers 5 and 25, you win $2.

Will you accept that bet?

Which Travels Faster? Solve below famous picture riddle:

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

An evil man kidnapped someone and made them take one of two pills. One was harmless, but the other was poisonous. Whichever pill the victim took, the kidnapper took the other one. The victim took their pill with water and died. The kidnapper survived. How did the kidnapper get the harmless pill?