WebAssign WEI TING LEE
Math 120 C, section C, Fall 2015
“mm” 7 9′” n ‘”°'”°w°’k) Instructor: PATRICK PERKINS
Current Score : – / 78 Due : Tuesday, October 27 2015 11:46 PM PDT
1. -/12 pointsUWAPreCalcl 7.9.010.
Rosalie is organizing a circus performance to raise money for a charity. She is trying to decide how
much
to charge for tickets. From past experience, she knows that the number of people who will attend is a
linear function of the price per ticket. If she charges 5 dollars, 1185 people will attend. If she
charges
7 dollars, 965 people will attend. How much should she charge per ticket to make the most money?
(Round your answer to the nearest cent.)
I:l
Additional Materials
Reading
2. -/12 pointsUWAPreCalcl 7.P.011.
A Norman window is a rectangle with a semicircle on top. Suppose that the perimeter of a particular
Norman window is to be 29 feet. What should the rectangle’s dimensions be in order to maximize the
area of the window and, therefore, allow in as much light as possible? (Round your answers to two
decimal places.)
width I:l h
height I:l ft
Additional Materials
Reading
3. -/12 pointsUWAPreCalcl 7.P.012.
Jun has 300 meters of fencing to make a rectangular enclosure. She also wants to use some fencing to
split the enclosure into two parts with a fence parallel to two of the sides. What dimensions should
the
enclosure have to have the maximum possible area? (Enter your answers as a comma-separated list.)
Additional Materials
Reading
4. -/12 pointsUWAPreCalcl 7.P.013.
You have $8000 with which to build a rectangular enclosure with fencing. The fencing material costs $30
per meter. You also want to have two partitions across the width of the enclosure, so that there will
be
three separated spaces in the enclosure. The material for the partitions costs $25 per meter. What is
the
maximum area you can achieve for the enclosure? (Round your answer to the nearest whole number.)
l:l m2
Additional Materials
0 Reading
5. -/16 pointsUWAPreCalcl 7.P.014.
Steve likes to entertain friends at parties with “wire tricks.” Suppose he takes a piece of wire 48
inches
long and cuts it into two pieces. Steve takes the first piece of wire and bends it into the shape of a
perfect circle. He then proceeds to bend the second piece of wire into the shape of a perfect square.
What should the lengths of the wires be so that the total area of the circle and square combined is as
small as possible? (Round your answers to two decimal places.)
length of wire for the circle E in
length of wire for the square :I in
What is this combined minimal area? (Round your answer to two decimal places.)
I:l in2
What should Steve do if he wants the combined area to be as large as possible?
He should make two circles, each with radius 24 inches.
He should make only a circle using all 48 inches of wire.
He should make two squares, each with side length 12 inches.
He should make a circle using 24 inches of wire, and a square using the rest of the wire.
He should make only a square using all 48 inches of wire.
Additional Materials
Reading
6. -/14 pointsUWAPreCalcl 7.P.017.
After a vigorous soccer match, fina and Michael decide to have a glass of their favorite refreshment.
They each run in a straight line along the indicated paths at a speed of 10 ft/sec.
(300. 200)
(-25! 175)
soy milk
beet juice
‘\(3:0. 50)
Tina
Michael
Write parametric equations for the motion of Tina and Michael individually after t seconds. (Round all
numerical values to four decimal places as needed.)
Tina x
y = I.-
Find when Tina and Michael are closest to one another. (Round your answer to four decimal places.)
t = I:l s
Find where Tina and Michael are closest to one another. (Round your answers to three decimal places.)
Tina (x, y)
Michael (x, y)
Compute this minimum distance. (Round your answer to one decimal place.)
I: ft
Additional Materials
0 Reading
3. 0/10 points I Previous AnswersUWAPreCalcl 7.P.005.
The initial price of buzz.com stock is $20 per share. After 20 days the stock price is $30 per share
and
after 40 days the price is $35 per share. Assume that while the price of the stock is not zero it can
be
modeled by a quadratic function.
(a) Find the multipart function s(t) giving the stock price after t days.
0 s t s 125
5(t)
t > 125
If you buy 1000 shares after 30 days, what is the cost?
I:l
(b) To maximize profit, when should you sell shares?
I:l days
How much will the profit be on your 1000 shares purchased in (a)?
I:l
Additional Materials
0 Reading,
4. -/10 pointsUWAPreCalcl 7.P.007.
A hot air balloon takes off from the edge of a plateau. Impose a coordinate system as pictured below
and assume that the path the balloon follows is the graph of the quadratic function
y = f(x) = – fig + gx. The land drops at a constant incline from the plateau at the rate of
1 vertical foot for each 5 horizontal feet. Answer the following questions.
height above plateau (feet)
0 balloon
takeoff
a – ‘ honzontal dtstance
from launch (feet)
-““‘~-___3 ground inclim
(a) What is the maximum height of the balloon above plateau level?
I:I ft
(b) What is the maximum height of the balloon above ground level?
I:l ft
(c) Where does the balloon land on the ground?
(XI Y)
(d) Where is the balloon 30 feet above the ground? (Round your answers to two decimal
places.)
(x, y)
-/z
(smaller x-value)
(x, y)
(larger x-value)
Additional Materials
0 Reading.