Abox contains 6 balls numbered from 1 to 6. john pulls a ball from the box, memorizes the number written on the ball and returns the ball in the box. then pedro does the same thing: he removes a ball from the box and memorizes the number written on the ball. what is the probability that john took the same number as peter?

Hello!

As the ball was replaced, the denominator in our probabilities will be the same. As the each had a 1/6 chance of getting the ball with the certain number, we just square the number as they both had the same probability.

1/6·1/6=1/36

There was a 1/36 chance of them selecting the same ball. This is also equivalent to about a 2.8% chance of this event occurring.

I hope this helps!