Your friend hides a dollar bill under one of three plastic cups. Under the other
two cups is a paper clip. You get to keep whatever is under the cup you
choose, but you don't know which contains the dollar bill. After you choose,
your friend lifts one of the other cups to reveal a paper clip and then gives you
the option of changing your choice.
Should you switch to the other cup?
A. No. The probability of winning the dollar is regardless of the cup
your choose.
B. Yes. If you switch cups, the probability of winning the dollar
increases from to 1/1.
OC. Yes. If you switch cups, the probability of winning the dollar is 3.
D. No. If you switch cups, the probability of winning the dollar is.