Who Has The Best Job (REMIX)


8.EE Who Has the Best Job? (REMIX)


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Alignments to Content Standards: 8.EE.B.5

Student View

Task

Kell works at an after-school program at an elementary school. The table below shows how much money he earned every day last week.


Monday Wednesday Friday
Time worked 1.5 hours 2.5 hours 4 hours
Money earned $12.60 $21.00 $33.60

Mariko has a job mowing lawns that pays $7 per hour.

  1. Who would make more money for working 10 hours? Explain or show work.

  2. Draw a graph that represents y, the amount of money Kell would make for working x hours, assuming he made the same hourly rate he was making last week.

  3. Using the same coordinate axes, draw a graph that represents y, the amount of money Mariko would make for working x hours.

  4. How can you see who makes more per hour just by looking at the graphs? Explain.

  5.  How much money would Kell and Mariko make each make in one year? (A work week is 40 hours and there are 52 weeks in a year)


Solution

  1. Mariko would make 7×10=70 dollars for working 10 hours. Kell's hourly rate can be found by dividing the money earned by the hours worked each day.

      Monday Wednesday Friday
    Time worked 1.5 hours 2.5 hours 4 hours
    Money earned $12.60 $21.00 $33.60
    Pay rate $8.40 per hour $8.40 per hour $8.40 per hour


    If Kell works for 10 hours at this same rate, he will earn 8.4×10=84 dollars. So Kell will earn more money for working 10 hours.

    Alternatively, we could reason proportionally without computing the unit rate.  Since Mariko earned $21.00 for 2.5 hours, she will earn four times as much for working four times as long (10=4×2.5), for a total of 4×$21=$84.

  2. See the figure below.

  3. See the figure below.

  4. You can see that Kell will make more per hour if you look at the points on the graph where x=1 since this will tell you how much money each person will make for working 1 hour. You can also compare the slopes of the two graphs, which are equal to the hourly rates. See the figure below.

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5.  Using the table above, we see that Kell makes $33.60 every 4 hours.  If we multiply this by 10 we will know how much Kell makes in a week, which is $336.00.  If we multiply by 52 (weeks) we get a total of $17, 472.00.

     Knowing that Mariko makes $7.00 per hour we can multiply this by 40 to get $280.00.  If we multiply this by 52 (weeks)  we will get $14,560.00.


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