How can you write nineteen in a manner that if we take out one, it becomes twenty?

When you stop to look, you can always see me. But if you try to touch me, you can never feel me. Although you walk towards me, I remain the same distance from you. What am I?

Can you solve below mathematical equation?

2^1234 - 2^1233

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

I know a nine-letter word having only one vowel.
Do you ?

What animal walks on four legs in the morning, two legs during the day, and three legs in the evening?

Oedipus, the king of Thebes, figured out the answer to the riddle:

Vin Diesel is pulling a theft and has planned to run away with all the cash kept in the safe. But the only way to open the safe is the 13 character password. He has a set of five clues given to him by a trustworthy source.

Exactly two of the below statements are false.
The password is contained within this sentence.
The password is not in this hint.
The password is within only one of these statements.
At least one of the above statements is a lie.

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

What's the next in the series?

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