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help_people

  • one year ago

@skullpatrol

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  1. help_people
    • one year ago
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    The number of subscribers y to a magazine after t years is shown by the equation below: y = 95(0.75)t Which conclusion is correct about the number of subscribers to the magazine? It increased by 25% every year. It decreased by 25% every year. It increased by 75% every year. It decreased by 75% every year.

  2. help_people
    • one year ago
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    i bleive this one is d

  3. mathstudent55
    • one year ago
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    Is t an exponent?

  4. help_people
    • one year ago
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    yes t is an expontnet @mathstudent55

  5. help_people
    • one year ago
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    ok @skullpatrol jstu to clarify d is wrong?

  6. help_people
    • one year ago
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    based on what you are showing me it is increasing

  7. skullpatrol
    • one year ago
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    yes

  8. skullpatrol
    • one year ago
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    $$\Huge y = 95(0.75)^t$$

  9. skullpatrol
    • one year ago
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    is that^ the equation?

  10. help_people
    • one year ago
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    yes @skullpatrol

  11. mathstudent55
    • one year ago
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    Calculate the function for t = 0. \(y = 95(0.75)^0 = 95 \times 1 = 95\) At t = 0, the initial numbers of subscribers is 95. Now let's calculate y for t = 1, at the end of 1 year. \(y = 95(0.75)^1 = 95 \times 0.75 = 71.25\) At t = 1, the end of the first year, the number of subscribers is 71.25. Now calculate the percent decrease from 95 to 71.25: \(percent~change = \dfrac{71.25 - 95}{95} \times 100 = -25\%\) A negative percent change is a decrease. The decrease is 25% per year.

  12. mathstudent55
    • one year ago
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    This problem can be solved without graphs or any calculations. All you need to do is to compare the equation you were given with the growth/decay formula: \(F = P(1 + r)^t\) where F = future amount, P = present amount r = rate of increase or decrease t = time in years If r is a rate of increase, then r is positive. A negative r means a rate of decrease. Now let's compare this formula with your given equation. \(y = 95(0.75)^t\) must fit into \(F = P(1 + r)^t\), then you get \(y = 95[1 + (-0.25)]^t\) Notice that to have 1 + r in the parentheses, you need to write 0.75 as 1 + (-0.25). This clearly shows that the rate is 25% decrease annually.

  13. help_people
    • one year ago
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    thank you

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