You are presented with three boxes. One of them has a red ball inside and the other two have a black ball inside each of them. You are asked to pick up the one with red ball and you pick one. Now, one of the other boxes is opened and it is found to have a black ball.

You are presented with a chance to change your box with the one that is left closed. Will you change your box? Why or why not?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

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

Can you find the largest Three-digit number whose sum is 14 and whose square is less than 5,00,000?

If 2 workers can complete painting 2 walls in exactly 2 hours.

How many workers would be needed to paint 18 walls in 6 hours?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

Your mother’s brother’s only brother-in-law is asleep on your couch. Who is asleep on your couch?

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

If a zookeeper had 100 pairs of animals in her zoo, and two pairs of babies are born for each one of the original animals, then (sadly) 23 animals don’t survive, how many animals do you have left in total?