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?

Carmen and matt are conducting different chemistry experiments in school. in both experiments, each student starts with an initial amount of water in a flask. they combine two chemicals which react to produce more water. carmen's experiment starts with 30 milliliters of water in a flask, and the water increases in volume by 8.5 milliliters per second. matt's experiment starts with 10 milliliters of water and increases in volume by 28% each second.