Equally likely outcomes

Can you help d'Alembert discover the probabilty of at least one head in two coin flips?

Your partner chooses two beads and places them side by side behind a screen. What is the minimum number of guesses you would need to be sure of guessing the two beads and their positions?

Will the witch make a profit or loss?

A bag contains red and blue balls. You are told the probabilities of drawing certain combinations of balls. Find how many red and how many blue balls there are in the bag.

Invent a set of three dice where each one is better than one of the others?