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Math Help - Functions - Problem Solving

  1. #1
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    Functions - Problem Solving

    I don't understand my teacher at all! Or maybe it's just me doing something wrong..?


    1) Shannon's mother brings her to an indoor playground. The admission costs $3 plus an additional fee for each half-hour of play. It costs $6 for Shannon to play for one hour. Graph the relationship.

    So I have two equations:

    y = 3 + (0.5)(x)(h) ---> x = fee
    6 = 3 + (0.5)(x)(2)

    What I don't understand is why my teacher wrote:

    6 = 3 + 3h

    2) An internet provider sets its rates according to the following scheme. It charges $1.25 to log-on with the service and an additional $0.25 for every 10 minutes online. Write an equation to represent the total charge, C, in dollars, as a function of time online, h (hours).

    This is the same type of question as the first one..
    The equation I got:

    10 minutes/60 minutes = 1/6
    C = 1.25 + (0.25)(1/6)(h)
    C = 1.25 + (1/24)(h)

    I don't understand why my teacher wrote this:

    C = 3.5h + 1.25



    Thanks in advance!
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  2. #2
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    Trumbull Ct
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    Exclamation Functions-problem solving

    Quote Originally Posted by Jiyongie View Post
    I don't understand my teacher at all! Or maybe it's just me doing something wrong..?


    1) Shannon's mother brings her to an indoor playground. The admission costs $3 plus an additional fee for each half-hour of play. It costs $6 for Shannon to play for one hour. Graph the relationship.

    So I have two equations:

    y = 3 + (0.5)(x)(h) ---> x = fee
    6 = 3 + (0.5)(x)(2)

    What I don't understand is why my teacher wrote:

    6 = 3 + 3h

    2) An internet provider sets its rates according to the following scheme. It charges $1.25 to log-on with the service and an additional $0.25 for every 10 minutes online. Write an equation to represent the total charge, C, in dollars, as a function of time online, h (hours).

    This is the same type of question as the first one..
    The equation I got:

    10 minutes/60 minutes = 1/6
    C = 1.25 + (0.25)(1/6)(h)
    C = 1.25 + (1/24)(h)

    I don't understand why my teacher wrote this:

    C = 3.5h + 1.25



    Thanks in advance!
    Your teacher wrote an equation for Shannon.You have to make it general and graph cost versus hours played .
    The second is similar but be careful
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  3. #3
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    For the first question though, why did he leave "h" there? We know Shannon played for 1 hour, which is two half-hours...

    Second question - how do I get 3.5 as the coefficient!?
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  4. #4
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    Quote Originally Posted by Jiyongie View Post
    I don't understand my teacher at all! Or maybe it's just me doing something wrong..?


    1) Shannon's mother brings her to an indoor playground. The admission costs $3 plus an additional fee for each half-hour of play. It costs $6 for Shannon to play for one hour. Graph the relationship.

    So I have two equations:

    y = 3 + (0.5)(x)(h) ---> x = fee
    6 = 3 + (0.5)(x)(2)

    What I don't understand is why my teacher wrote:

    6 = 3 + 3h

    2) An internet provider sets its rates according to the following scheme. It charges $1.25 to log-on with the service and an additional $0.25 for every 10 minutes online. Write an equation to represent the total charge, C, in dollars, as a function of time online, h (hours).

    This is the same type of question as the first one..
    The equation I got:

    10 minutes/60 minutes = 1/6
    C = 1.25 + (0.25)(1/6)(h)
    C = 1.25 + (1/24)(h)

    I don't understand why my teacher wrote this:

    C = 3.5h + 1.25



    Thanks in advance!
    Shannon's equation defined the hourly rate as $3 per hour so C=3 +3 h.
    The second is similar.Do it the same way and assume the teacher throws curves or made a mistake


    bjh
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  5. #5
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    Quote Originally Posted by Jiyongie View Post
    I don't understand my teacher at all! Or maybe it's just me doing something wrong..?


    1) Shannon's mother brings her to an indoor playground. The admission costs $3 plus an additional fee for each half-hour of play. It costs $6 for Shannon to play for one hour. Graph the relationship.

    So I have two equations:

    y = 3 + (0.5)(x)(h) ---> x = fee
    6 = 3 + (0.5)(x)(2)

    What I don't understand is why my teacher wrote:

    6 = 3 + 3h
    what u did is right. but we want h to be a variable and x to be a constant.

    since the addition charge or cost is fixed (ie not a percentage cost).

    so you rearrange to find x.

    6 = 3 + (0.5)(x)(2)
    3=1x
    x=3

    so the overall equation = y=3+3h
    where y varies with h.

    hope this helps.
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