John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?

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?

Which is the smallest number that you can write using all the vowels exactly once?

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?

A Car driver was heading down a street in Washington. He went right past a stop sign without stopping, he turned left where there was a 'no left turn' sign and he went the wrong way on a one-way street. Then he went on the right side of the road past a cop car. Still, he didn't break any traffic laws. Why not?

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

On rolling two dices (six-sided normal dice) together, what is the probability that the first one comes up with a 2 and the second one comes up with a 5?

What 5-letter word typed in all capital letters can be read the same upside down?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?