Practice Problems for the Lander Math Contest
Module 2, Problems (4-6):
4) A pair of fair dice is tossed. Find the probability that at
least one die shows a 3.
5) A red bag contains 4 black and 3 white marbles. A yellow
bag contains 2 black and 5 white marbles. A fair coin is
tossed. If the coin turns up heads, a single marble is taken
from the red box. If it turns up tails, single marble is taken from
the yellow box. Find the probability that the marble taken is
6) A fair coin is tossed four times. What is the probability of
having precisely two heads?