I know a 5-digit number having a property that With a 1 after it, it is three times as large as it would be with a one before it.

Guess the number?

Which of the following words don't belong in the group and why?
CORSET, COSTER, SECTOR, ESCORT, COURTS

I’m tall when I’m young, and I’m short when I’m old. What am I?

I’m tall when I’m young, and I’m short when I’m old. What am I?

In a concert, Christina is performing a dance show with her group.
At 10:00, she and her crew were dancing in an absolutely straight line. At that time Christina was standing in 4th position from both the front and back end of the row.

What was the size of her crew?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

Known by all without exception, Forever here, for your protection, Sometimes strong, sometimes weak, Right after the night I come - hot and chic. And while millions of miles away, I always get to you, I find my way. No life around could do without me, Can you guess what I might be?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

I am a five-letter word and people eat me. If you remove the first letter I become an energy form. If you remove the first two letters, I am needed to live. Scramble the last three letters and I am a drink. What word am I?