Chapter 2 - MDC Faculty Home Pages

98) Given the revenue and cost functions R = 30x - 0.3x2 and C = 3x + 13, where x is the daily
production, find the rate of change of profit with respect to time when x = 10 units and
dx
= 8 units per day.
dt
A) $168 per day B) $192 per day C) $211.2 per day D) $210 per day
99) A heart attack victim is given a blood vessel dilator to increase the radii of the blood vessels. After
receiving the dilator, the radii of the affected blood vessels increase at about 2% per minute.
According to Poiseulle's law, the volume of blood flowing through a vessel and the radius of the
vessel are related by the formula V = kr4 where k is a constant. What will be the percentage rate of
increase in the blood flow after the dilator is given?
A) 8%/min B) 6%/min C) 12%/min D) 10%/min
100) A zoom lens in a camera makes a rectangular image on the film that is 8 cm length x 5 cm width.
As the lens zooms in and out, the size of the image changes. Find the rate at which the area of the
image begins to change (dA/df) if the length of the frame changes at 0.5 cm/s and the width of the
frame changes at 0.1 cm/s.
A) 3.3 cm2/s B) 8
5 cm2/2 C) 0.66 cm2/s D) 4.5 cm2/s
28
PDF Created with deskPDF PDF Writer - Trial :: http://www.docudesk.com
98)
99)
100)