Rachel and her little sister Christie often argue about who should wash the dishes at their house. Rachel suggests that
they flip coins to solve their argument.
"Flipping a coin is fair, since heads and tails each have an equal chance of happening. Each one has a probability
of" Rachel says. "If the coin shows heads, then I do the dishes. If it shows tails, then you do them."
a. Is this system fair? That is, does each girl have an equal likelihood of washing the dishes each day? What is
the theoretical probability for heads? For tails?
b. Rachel and Christie flip a coin every evening for the first week. Christie has washed the dishes four times, and Rachel has washed the dishes three
times. Christie tells Rachel that the system is not fair, because Christie has done the dishes more often than Rachel. Is Christie right?
c. After the second week of coin flipping, Christie has washed the dishes ten times and Rachel has washed the dishes four times. Now Christie is
really upset at Rachel because she has washed the dishes so many times.