Can you divide numbers from 1 to 9 (1 2 3 4 5 6 7 8 9) into two groups so that the sum of the numbers of each group is equal?

Note: 9 cannot be turned over to make it 6.

You need to climb ten stairs. At every stair, you can either take one step up or you can jump two steps up.

In how many different ways you can climb 10 stairs?

You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?

You are driving down the road in your car on a wild, stormy night, when you pass by a bus stop and you see three people waiting for the bus

An old lady looks as if she is about to die.
An old friend who once saved your life.
The perfect partner you have been dreaming about.
Knowing that there can only be one passenger in your car, whom would you choose?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

I had an infinite supply of water and 5 litres and 3 litres jars.

How would you measure exactly 4 litres in the least number of steps?

A woman lives in a skyscraper thirty-six floors high and is served by several elevators which stop at each floor going up and down. Each morning she leaves her apartment and goes to one of the elevators. Whichever one she takes is three times more likely to be going up than down. Why?

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?

If,

Akriti = 631
Levis = 521
Sroti = 521
Aneel = 533
Then,
Sunil =?

Complete the series by replacing "?" with the correct number.

ST ND RD TH '?'