Question 1

Of all the topics we have covered in unit 3, what has stood out to you as something most relevant
to your life? Explain why.

Accepted Answer

The answer of Of all the topics we have covered...

Question 2

Mountain climbers use a general rule of thumb which estimates that the temperature will drop 3.5 degrees Fahrenheit for every 1000 ft of elevation. 
 b. Find the slope of the line and explain what it means.
c. Find the y-intercept and explain what it means.
d. Write the equation of the line.
e. Restate your equation in the form of a sentence: "If x represents …, then y = … represents …"
f. Use your equation to find the temperature at 10,000 ft.

Accepted Answer

The answer of Mountain climbers use a general rule of...

Question 3

B  varies directly as  m  and inversely  n . B=36  when  m=54  and  n=9 , find  B  when  m=  7 and  n=5 .
A)

B)

C)

D)

Accepted Answer

The answer of  B  varies directly as ...

Question 4

The following table reports the number of yellow fever cases reported in Ghana for the years 1992-2004 (after the start of mass immunization).  b. What trends do you see? Be specific.

Accepted Answer

The answer of The following table reports the number of...

Question 5

Find the slope of the line connecting the points 
A)

B)

C)

D)

Accepted Answer

The answer of Find the slope of the line connecting...

Question 6

The cost, in dollars, of filling your gas tank is directly proportional to the price per gallon of gas. If 8 gallons of gas costs $10.00, how much would 11 gallons cost?
A)$15.00
B)$11.25
C)$13.75
D)$13.00

Accepted Answer

The cost of 8 gallons is $10.00, so the cost per gallon is $10.00 / 8 = $1.25. For 11 gallons, the cost would be 11 * $1.25 = $13.75.

Question 7

The table displays the number of women in the US House of Representatives for selected years from 1980 through 2008.  
a. Use your calculator to determine the line of best fit for these data, where x is the number of years since 1980. Round all coefficients to 4 decimal places.
b. What is the correlation coefficient, r? What does it mean about whether this line is a good fit for these data? Explain.
c. Give the slope of the line and explain what it means.
d. Use this equation to predict the number of women in the House of Representatives in the year 2013.

Accepted Answer

The answer of The table displays the number of women...

Question 8

My spouse was recently in Mexico, and I had to determine the cheapest way to call. AT&T has an international wireless plan called World Connect with a monthly fee of $3.99, and then my calls to a Mexican landline are $0.09 per minute. Without this plan, I would pay no monthly fee and $0.49 per minute.
a. Write equations for the cost C of each option.
I'm using the letter _______________ to represent the variable quantity __________.
b. Solve the system of equations you wrote in part a to find the number of minutes for which the two options would cost the same. (Round to the nearest whole minute.)When would it make sense to pay for the World Connect plan?

Accepted Answer

The answer of My spouse was recently in Mexico, and...

Question 9

L  varies jointly as  a  and the square root of  b . If  L=160  when  a=5  and  b=16 , find  L  when  and  b=144 .
A)  L=384 
B)  L=32 
C)  L=4 
D)  L=96

Accepted Answer

The answer of  L  varies jointly as ...

Question 10

The following table shows the cost of renting a full-size rental car, based on the number of miles
driven.  
a. Explain why a linear equation is appropriate for this relationship.
b. Find the slope of the line and explain what it means.
c. Find the y-intercept and explain what it means.
d. Determine the equation of the line.
e. Is this a direct variation relationship? Why or why not? Be specific.
f. I am trying to decide whether I can afford to rent a full-size car to drive to St. Louis, which is about 180
miles away. How much would that cost for a one-way trip? How much would it cost for a round trip of 360
miles?
g. Why doesn't the round trip cost twice as much as the one-way trip? Be specific.

Accepted Answer

The answer of The following table shows the cost of...

Question 11

True story from Erin's life: My 4-month old daughter got her shots, and we ended up needing to give her some tylenol for the pain. Infant Tylenol comes in liquid form, and the box indicates that there are 160 mg of
acetaminophen per 5 mL of liquid.
a. Complete the table, and then use it to draw a graph, where x is the amount of infant Tylenol in mL and y is the amount of acetaminophen in mg. 
 b. Is this a direct variation relationship? Why or why not? Be specific.
c. Find the slope of the line you graphed and explain what it means.
d. Write a linear equation that describes the amount of acetaminophen in mg (y)in terms of mL of infant tylenol (x).
e. In spite of the handy SimpleMeasure syringe, the directions don't give a dosage for children
under 2 years old. This is because it depends on weight and they want you to call the doctor so you don't get the math wrong. But I'm a math teacher, so I looked it up. For my daughter's weight at that time, the dosage is 115 mg of acetaminophen. How many mL of infant Tylenol did I need to give her?

Accepted Answer

The answer of True story from Erin's life: My 4-month...

Quiz 3: Thinking Linearly

Of all the topics we have covered in unit 3, what has stood out to you as something most relevant to your life? Explain why.

B varies directly as m and inversely n . B=36 when m=54 and n=9 , find B when m= 7 and n=5 .

The following table reports the number of yellow fever cases reported in Ghana for the years 1992-2004 (after the start of mass immunization). b. What trends do you see? Be specific.

Find the slope of the line connecting the points

The cost, in dollars, of filling your gas tank is directly proportional to the price per gallon of gas. If 8 gallons of gas costs $10.00, how much would 11 gallons cost?

L varies jointly as a and the square root of b . If L=160 when a=5 and b=16 , find L when and b=144 .