An 18 gram sample of a substance that's used to detect explosives has a k value of 0.215
Find the substance's half-life in days, Round your answer to the nearest tenth
N = Noe k

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?