1.4E: Exercises - Linear Applications (2024)

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    PROBLEM SET: LINEAR APPLICATIONS

    In the following application problems, assume a linear relationship holds.

    1) The variable cost to manufacture a product is $25 per item, and the fixed costs are $1200.
    If x is the number of items manufactured and
    y is the cost, write the cost function.

    2) It costs $90 to rent a car driven 100 miles and $140 for one driven 200 miles. If x is the number of miles driven and y the total cost of the rental, write the cost function.

    3) The variable cost to manufacture an item is
    $20 per item, and it costs a total of $750 to produce 20 items. If x represents the number
    of items manufactured and y is the cost, write the cost function.

    4) To manufacture 30 items, it costs $2700, and to manufacture 50 items, it costs $3200. If x represents the number of items manufactured and y the cost, write the cost function.

    5) To manufacture 100 items, it costs $32,000, and to manufacture 200 items, it costs $40,000. If x is the number of items manufactured and
    y is the cost, write the cost function.

    6) It costs $1900 to manufacture 60 items, and the fixed costs are $700. If x represents the number of items manufactured and y the cost, write the cost function.

    7) A person who weighs 150 pounds has 60 pounds of muscles; a person that weighs 180 pounds has 72 pounds of muscles. If x represents body weight and y is muscle weight, write an equation describing their relationship. Use this relationship to determine the muscle weight of a person that weighs 170 pounds.

    8) A spring on a door stretches 6 inches if a force of 30 pounds is applied. It stretches 10 inches
    if a 50 pound force is applied. If x represents the number of inches stretched, and y is the force, write a linear equation describing the relationship. Use it to determine the amount of force required to stretch the spring 12 inches.

    9). A male college student who is 64 inches tall weighs 110 pounds. Another student who is 74 inches tall weighs 180 pounds. Assuming the relationship between male students' heights (x), and weights (y) is linear, write a function to express weights in terms of heights, and use this function to predict the weight of a student who is 68 inches tall.

    10) EZ Clean company has determined that if it spends $30,000 on advertising, it can hope to sell 12,000 of its Minivacs a year, but if it spends $50,000, it can sell 16,000. Write an equation that gives a relationship between the number of dollars spent on advertising (x) and the number of minivacs sold(y).

    11) The freezing temperatures for water for Celsius and Fahrenheit scales are 0ºC and 32ºF. The boiling temperatures for water are 100 ºC and 212 ºF. Let C denote the temperature in Celsius and F in Fahrenheit. Write the conversion function from Celsius to Fahrenheit. Use the function to convert 25 ºC into ºF.

    12) By reversing the coordinates in the previous problem, find a conversion function that converts Fahrenheit into Celsius, and use this conversion function to convert 72 ºF into an equivalent Celsius measure.

    13) California’s population was 29.8 million in the year 1990, and 37.3 million in 2010. Assume that the population trend was and continues to be linear, write the population function. Use this function to predict the population in 2025. Hint: Use 1990 as the base year (year 0); then 2010 and 2025 are years 20, and 35, respectively.)

    14) Use the population function for California in the previous problem to find the year in which the population will be 40 million people.

    15) A college’s enrollment was 13,200 students in the year 2000, and 15,000 students in 2015. Enrollment has followed a linear pattern.
    Write the function that models enrollment as a function of time. Use the function to find the college’s enrollment in the year 2010.
    Hint: Use year 2000 as the base year.

    16) If the college’s enrollment continues to follow this pattern, in what year will the college have 16,000 students enrolled.

    17) The cost of electricity in residential homes is a linear function of the amount of energy used. In Grove City, a home using 250 kilowatt hours (kwh) of electricity per month pays $55.
    A home using 600 kwh per month pays $118. Write the cost of electricity as a function of the amount used. Use the function to find the cost for a home using 400 kwh of electricity per month.

    18) Find the level of electricity use that would correspond to a monthly cost of $100.

    19) At ABC Co., sales revenue is $170,000 when it spends $5000 on advertising.
    Sales revenue is $254,000 when $12,000 is spent on advertising.

    a) Find a linear function for
    y = amount of sales revenue as a function of
    x = amount spent on advertising.

    b) Find revenue if $10,000 is spent on advertising.

    c) Find the amount that should be spent on advertising to achieve $200,000 in revenue.

    20) For problem 19, explain the following:

    1. Explain what the slope of the line tells us about the effect on sales revenue of money spent on advertising. Be specific, explaining both the number and the sign of the slope in the context of this problem.
    2. Explain what the y intercept of the line tells us about the sales revenue in the context of this problem

    21) Mugs Café sells 1000 cups of coffee per week if it does not advertise. For every $50 spent in advertising per week, it sells an additional 150 cups of coffee.

    a) Find a linear function that gives
    y = number of cups of coffee sold per week
    x = amount spent on advertising per week.

    b) How many cups of coffee does Mugs Café expect to sell if $100 per week is spent on advertising?

    22) Party Sweets makes baked goods that can be ordered for special occasions. The price is $24 to order one dozen (12 cupcakes) and $9 for each additional 6 cupcakes.

    1. Find a linear function that gives the total price of a cupcake order as a function of the number of cupcakes ordered
    2. Find the price for an order of 5 dozen (60) cupcakes
    1.4E: Exercises - Linear Applications (2024)

    FAQs

    How do you solve linear E? ›

    The steps for solving linear equations are:
    1. Simplify both sides of the equation and combine all same-side like terms.
    2. Combine opposite-side like terms to obtain the variable term on one side of the equal sign and the constant term on the other.
    3. Divide or multiply as needed to isolate the variable.
    4. Check the answer.
    Oct 6, 2021

    How do you calculate linear E? ›

    Using the slope-intercept form, the linear equation can be found using y = mx + c and using the point-slope form, it can be found using y - y1 = m(x-x1), where m is the slope, c is the y-intercept, and (x1, y1) is a point on the line.

    What is an example of a linear equation in one variable? ›

    The linear equations in one variable is an equation which is expressed in the form of ax+b = 0, where a and b are two integers, and x is a variable and has only one solution. For example, 2x+3=8 is a linear equation having a single variable in it. Therefore, this equation has only one solution, which is x = 5/2.

    How are linear equations used in everyday life? ›

    Applications of Linear Equations in Real life

    It is used to calculate speed, distance and time of a moving object. Geometry related problems can be solved. It is used to calculate money and percentage related problems. Work, time and wages problems can be solved.

    Why are linear equations so hard? ›

    Difficulty in linear algebra also arises because you first need to understand terms and different definitions. Once you are through with that step, determine the kind of calculation and the specific analysis to apply to get the required outcome.

    What does the e mean in linear? ›

    It is often called Euler's number and, like pi, is a transcendental number (this means it is not the root of any algebraic equation with integer coefficients).In derivatives The function f(x) = e. x. is called the (natural) exponential function, and is the unique exponential function of type a.

    How do you simplify a linear equation? ›

    To solve linear equations, find the value of the variable that makes the equation true. Use the inverse of the number that multiplies the variable, and multiply or divide both sides by it. Simplify the result to get the variable value. Check your answer by plugging it back into the equation.

    What are 5 examples of linear equation in two variables? ›

    The following are examples of two-variable linear equations:
    • 3 x + 5 y = 7 \displaystyle 3x + 5y = 7 3x+5y=7.
    • y = 2 3 x − 3 \displaystyle y = \frac{2}{3}x - 3 y=32​x−3.
    • ( y − 2 ) = − 2 7 ( x + 3 ) \displaystyle \left(y-2\right)=\frac{-2}{7}\left(x+3\right) (y−2)=7−2​(x+3)

    What are the rules for solving linear equations? ›

    The following steps provide a good method to use when solving linear equations.
    • Simplify each side of the equation by removing parentheses and combining like terms.
    • Use addition or subtraction to isolate the variable term on one side of the equation.
    • Use multiplication or division to solve for the variable.

    What are 4 examples of linear equations? ›

    Some of the examples of linear equations are 2x – 3 = 0, 2y = 8, m + 1 = 0, x/2 = 3, x + y = 2, 3x – y + z = 3. In this article, we are going to discuss the definition of linear equations, standard form for linear equation in one variable, two variables, three variables and their examples with complete explanation.

    What is a practical example of a linear equation? ›

    You can use a linear equation to determine the cost of whatever cab trip you take on your vacation without knowing how many miles it will be to each location. For example, the linear equation would be y = 0.15x + 9 if “x” represents the number of miles to your destination and “y” represents the cost of that taxi fare.

    How to solve linear regression? ›

    Calculating the Linear Regression

    The equation is in the form of “Y = a + bX”. You may also recognize it as the slope formula. To find the linear equation by hand, you need to get the value of “a” and “b”. Then substitute the resulting value in the slope formula and that gives you your linear regression equation.

    How do I solve a linear function? ›

    Solving Linear Functions
    1. Substitute the value of f(x) into the problem. In this case: ...
    2. Isolate the variable. In this case, you add 1 to both sides to isolate the variable term by using the opposite operation to move the constant term across the equal sign. ...
    3. Continue to isolate the variable. ...
    4. Simplify.

    What is simple linear e? ›

    A linear equation in one variable is an equation that can be written in the form. a x + b = 0 , where a , b ∈ Q and. A linear equation that has only one variable is a simple equation. The value of the variables that makes the equation true, i.e., makes L.H.S. equal to R.H.S. is called the solution of the equation.

    What is the formula for a linear exponential function? ›

    Linear function - has the form y = mx + b where the rate of change is constant m. Graph is a straight line. Exponential function - has the form y = a^x, where the rate of change is NOT constant and is different for different values of x.

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