If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

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?

There is a place where if I stand up straight, I will still be considered sideways.

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

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?

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

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

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

How many letters are in the alphabet?

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?