The height h(t) of an arrow is modeled by h(t)=-3ť +21t+6 where t is time in seconds. What is the maximum height reached by the arrow, and when does it occur?
A) 38.75 whent=3.5 sec
C) 42.75 whent=3.5sec
B) 38.75 whent=7sec
D) 42.75 whent=7sec

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?