What number should come in place of the question mark below?

Jessica is telling her friends this story and asks them to guess if it’s the truth or a lie: “There was a man sitting in a house at night that had no lights on at all. There was no lamp, no candle, and no other source of light. Yet, he sat in the house and read his book happily.” Her friends say she’s lying, but Jessica corrects them and says she’s telling the truth. Jessica’s story is true—but how?

The day after tomorrow will be three days before Tuesday. Can you find out what is today?

If eleven plus two equals one, what does nine plus five equal?

Find the Odd One Out?
84129
32418
47632
36119
67626
72927

You know three triplets: Frank John and Wayne (need to return your money). Frank always tells the truth while John and Wayne always lie. You meet one of them on the road and can ask him a three-word question.
Which question, will you ask?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

Suppose we lay down two cups in front of you. One of the cups is filled with tea and the other one with coffee. Now we ask you to take a spoonful of tea and mix it with the coffee. At this moment, the coffee cup has a mixture of tea and coffee. You have to take that mixture (spoonful) and add it back to the tea.

Can you now tell if the cup of coffee has more tea or the cup of tea has more coffee?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

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