What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

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?

Can you count the number of matches in the picture below ?

I was born in a small house and I live in it all alone. No windows and no doors have been assigned to my house. The only way I can go out is by breaking through the walls of my house.

Who am I?

The current time can be represented by below textual rebus.

0
=========
B.Sc
LLB

Can you tell us the current time?

I am a normal creature, but I have five hands. I can even have more but even then I will be considered normal.

Who am I?

Why is 6 afraid of 7?

A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?