When can we add 2 to 11 and get 1 as the correct answer?

The doctor prescribed you to take one pill from the bottle every half an hour. The bottle is now left with only three pills.

How long do you think you have before you run out of pills?

Which alphabet letter is a question?

I am the beginning of the end, and the end of time and space. I am essential to creation, and I surround every place. What am I?

What is full of holes but still holds water?

Three ants are sitting at the three corners of an equilateral triangle. Each ant starts randomly picks a direction and starts to move along the edge of the triangle. What is the probability that none of the ants collide?

A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

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