A minimum of four colors is needed to color a map so that no two countries that directly share borders have the
same color. This rule is true:
for no maps, three is the minimum.
for some maps, depending on the map.
for all maps.

Afootball quarterback has two more chances to throw a touchdown before his team is forced to punt the ball. he misses the receiver on the first throw 25% of the time. when his first throw is incomplete, he misses the receiver on the second throw 15% of the time. what is the probability of not throwing the ball to a receiver on either throw?