When it's bad luck to meet a black cat?

John speaks the truth only once a day in a week. Below are a few hints for you:

First: Days are Sunday, Monday and so on.
Second: One day he says, "I lie on Monday and Tuesday".
Third: On the next day, he says, "Today is either Thursday, Saturday or Sunday".
Fourth: On the next day, he says, "I lie on Wednesday and Friday".

Can you identify the day on which he speaks the truth?

A Child was born in Lahore, Pakistan.

Still child is not a Pakistani citizen.why ?

An ant is travelling on a 1-meter-long rope at 1 cm/second but also the entire rope is being stretched by an extra 1 meter/second. Is it possible for the ant to reach at the end of the rope?

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

Give it food and it will live; give it water and it will die.

Which number should replace the question mark?

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?