108 Chapter 2: Differentiation
c. cubic inches per second
d. cubic inches per second
e. cubic inches per second
____ 19. The ordering and transportation cost C for the components used in manufacturing a
product is where C is measured in thousands of dollars and x is the
order size in hundreds. Find the rate of change of C with respect to x for x = 24. Round your answer
to two decimal places.
a. –6.44 thousand dollars per hundred
b. 8.04 thousand dollars per hundred
c. 3.28 thousand dollars per hundred
d. –4.92 thousand dollars per hundred
e. –7.96 thousand dollars per hundred
____ 20. A population of 620 bacteria is introduced into a culture and grows in number
according to the equation where t is measured in hours. Find the rate at
which the population is growing when t = 2. Round your answer to two decimal places.
a. 226.7 bacteria per hour
b. 68.89 bacteria per hour
c. 65.26 bacteria per hour
d. 51.52 bacteria per hour
e. 61.23 bacteria per hour
____ 21. When satellites observe Earth, they can scan only part of Earth’s surface. Some
satellites have sensors that can measure the angle shown in the figure. Let h represent the satellite’s
distance from Earth’s surface and let r represent Earth’s radius. Find the rate at which h is changing
with respect to when (Assume r = 4460 miles.) Round your answer to the nearest unit.