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.

I am a five-letter word and comprises two different vowels and three same consonants. I am so strong that I can spoil your entire work.

Can you find out who am I?

Accidentally, two trains are running in the opposite direction and enter a tunnel that is 200 miles long. A supersonic bird that has fled the lab and taken shelter in the tunnel starts flying from one train towards the other at a speed of 1000 mph. As soon as it reaches the second train, he starts flying back to avoid collision and meets the first train again at the other end. The bird keeps flying to and fro till the trains collide with each other.

What is the total distance that the supersonic bird has traveled till the trains collided?

While house hunting in London, I came across a very good leasehold property Discussing the lease the landlady told me:

'The property was originally on a 99 years lease and two-thirds of the time passed is equal to four-fifths of the time to come. Now work it out for yourself and see how many years are to go!

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

If a wheel has 54 spokes, how many spaces are there between the spokes?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

What brings you down but never up?