Question

Graph All the plans on the graph provided. Your graph should include talk times between 0 and 200 minutes.

Answer 1

I'll do the first five problems to get you started.

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Problem 1

The graph is shown below in the attached image.

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Problem 2

The plan chosen was Public Mobile, which offered $24 per month for unlimited minutes. This plan does not depend on the number of minutes, so this is not a direct variation. It's also not a partial variation either since the cost doesn't vary (ie change) at all. The monthly cost is fixed at $24 per month.

Even at 200 minutes, this is the cheapest plan as mentioned in the other chart I posted. You can determine this by plugging x = 200 into each equation described earlier. You should find that Public Mobile still gives the cheapest rate. The graph done in problem 1 visually verifies this. The gray line y = 24 is below each of the other lines when x = 200.

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Problem 3

The best plan is still Public Mobile when x = 1800 minutes per month.

Any x value such that x > 140 will also have Public Mobile be the best plan.

When we get to x = 140 is when this isn't the best plan and instead Bell is the better plan to go with. Note the purple line y = 0.10x+10 is below the gray line y = 24 for values x < 140. This visually shows us that Bell is cheaper compared to Public Mobile.

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Problem 4

The plan with the greatest rate of change is Telus. This is because y = 0.35x has the largest slope of 0.35

The rate of change is the charge per minute.

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Problem 5

If you talked for 200 minutes, then Public Mobile is the best plan. This is because the gray line y = 24 is below any other line when we have x = 200.