How can you take 2 from 5 and leave 4?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

Two friends Smith and Andrew were talking about the bravery of their families. Smith told great stories about his courageous grandfather who fought for Britain in "World War I". Andrew told that his grandfather was so brave that in 1919 just after the war he was honoured with a bravery medal with the words "For our Courageous Soldiers In World War I" embedded into it. Smith knows that his friend is lying. How?

What is both possible and impossible at the same time?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

Bopanna was working on a murder case when he received a message about the location of the murder weapon.
The message was encrypted as below.

"deb mitciv eht edisni neddih si nopaew redrum ehT"

Tell me the location of the murder weapon.