20.
relief donations the number of private donations
received by nongovernment disaster relief organizations can
be modeled as
f(x) = 0.3xe -0.03x thousand donations
where x is the number of hours since a major disaster has
struck
a. write an expression for the rate of change in donations.
b. at what time is the rate of change of donations zero?
c. what is the donation level at the time found in part b?

You drop a rubber ball off the roof of a 50 meter high building onto a paved parking lot. it bounces back up with every bounce, but not quite all the way back up to you. after the first bounce it bounces back only 80 percent of the distance it was dropped from. the pattern continues, meaning after every bounce it comes up to just 80 percent of the previous maximum height. so if before the first bounce the height is 50 meters, what height does the ball reach after the fifth bounce? round your answer to one decimal place and chose the correct response from the choices below: